There are times when one handed operation is absolutely essential i.e taking notes whilst on the landline and responding to a text or email. As a former property manager I can tell you there have been countless time critical scenarios. If you aren't a hands-on property manager, then you are just a glorified call rep.
Yes, there are. Because of this thread, I have been purposefully trying to use my phone with one hand as I do other things. I have discovered that there are a number of things that I have been doing one handed and didn't realize until I became conscious of it. Things I wouldn't necessarily recommend for others to do one handed. I'll discuss that toward the bottom of this post after all the quotes.
As RumouredNow mentioned in an earlier post, we humans are by nature are adaptable. Some people don't like change as change comes at a price; never the less it is inevitable as the nature of technology is progressive. MS are moving to design which they feel is progressive and which will appeal to a variety of audiences. You don't need to go beyond the xbox one controller to see which direction they were heading; never the less even if they ship with the hamburger icons; don't forget these are update-able universal store apps.
Yes, we are adaptable. Also, to be expanded below, because it goes with the one above.
Lastly, majority of the smartphone UX design being geared to right handers I imagine that is because either majority of the testers are right handers, ambidextrous or are left handers who have adapted to using a smartphone with their right hand (I know plenty of lefties who use their phones with their right hands). Personally I would say the world in general in terms is geared to right hand use. i.e most kitchenware, scissors, certain mouse models, certain ring binders, certain physical notepads, the location of the trackpad in laptops and so on.
Yes, the majority are right-handed persons, which has helped me to come to a very surprising conclusion about which hand I use for my phone.
Okay, now for my discussion, which will touch on all the above.
I have discovered that when I am just using my phone casually, I'll use my right hand "most" of the time. However, any time I am doing something else that is a "primary" action, (such as taking notes, opening a door, etc.) I find that I have my phone in my left hand and that I am as capable using it in my left hand as in my right. I don't know how or when that happened, but it is something I noticed as I have been more conscious of it since starting participation in this thread.
You must also realize that when I first got the phone, I was unable to use it in one hand and even found it difficult to use with two hands without dropping it. Why? Because the Lumia 635 comes with a very slick case. I also have short fingers which exacerbates the problem. What did I do about this? I adapted. Or, should I say, I started by adapting my phone. I bought a rugged case that has ribs on the back of it, and a good rubberized feel that makes it quite easy to grip with one hand without dropping it.
With this case, I have adapted to become very nimble with it. I can, using my fingers on the backside of the phone, manipulate the phone up and down quickly in order to reach all areas of the phone, without ever losing balance of the phone. Can everyone adapt to this? I doubt it. I'm sure that some could, but it takes using the proper tools. Tools are the main way man has adapted to things since the beginning of time. My tool was a case. I didn't really purchase it so much to be able to use the phone with one hand, I got the case to keep it from being so slippery, because I was unable to even hold the phone without a case.
Now, the case made the phone bigger, and harder to reach areas of the screen. I have, however, adapted to reach. Having the short fingers has made me learn how to do a lot of things differently from the way other people do things, but I've learned how to get things to work. I do find myself preferring to use two hands whenever possible.
If I'm busy with my hands in most cases, I don't need to stop what I'm doing to answer the phone because I have a Voyager Legend Bluetooth headset that I wear all day long. There are some people that say, "I wouldn't be caught dead out in public with that headset protruding out of my ear." To them I say, "It sure looks better than a large phone covering half my face everywhere I go." Honestly, some people can't seem to walk in public without a large phone constantly up against their face. I know most people don't like to wear headsets, but this one is comfortable for me, it is waterproof, stops background and wind noise quite well, and I can use my voice to answer or reject calls. That means I never have to touch my phone if I receive a call or a text. (Cortana handles the text part quite nicely, my Bluetooth handles answering or rejecting the call.) That means I can keep washing the car, changing the spark plugs, changing a diaper, or even washing dishes. We all hate to have to grab our phone if we've got our hands either greasy or soapy, or even something else while changing a diaper. Yeah, been there.
I find that I only need to pull my phone out when calling into a customer service center, and I have to press "1" or "5" or whatever, as far as making calls go. When it comes to "non phone call features", there are some of those I need to get out the phone to handle the phone for. However, Cortana keeps me from having to do very much handling, which I really like. Now that I can dictate emails, things have gotten even easier.
95% of the time, when I need to use my hands for my phone at all in Windows 10, it is because I am either checking emails while I'm out, which is rare, or because I've decided to play a game. Oh, and since the Windows 10 tech preview, I am also having to use my hands to manually open and check the weather, because Cortana no longer knows my accurate location. She's now locating me by my IP address instead of my GPS location. ?!? Irritating. I can't ask her for current temperature, forecast, or anything, because she gives it to me for another state (which varies which state). I'll be glad when that's fixed. Every other app knows my correct location except Cortana, and she's the one I need it for the most.
Pressing the call button while not in a call will bring up Cortana. This is a must have for me. I don't have to pull out my phone. Heck, my phone can be on a table in the next room, and I don't have to worry about it in most cases. And, with the battery life on this preview, it is in the next room on the charger a lot of the time, so I'm very dependent on my Bluetooth headset, Cortana, and some other speech enabled apps that I use.
As far as one handed operation goes, I find that, for me, pressing the hamburger menu is actually easier than doing the sideways swipe. Like I said, I have short fingers. The sideways swiping is the one motion that makes me want to drop the phone, because I put weight from one side to the other of the phone, and I am unable to hold it all the way across on the back, so it tilts over and tries to drop. Irritating. I realize, however, that I am in a minority here. I never complained about swiping back and forth to get to things, even though I hated it. I just worked on trying to adapt to it. To me, it seemed like a stupid way to get things done. I re-iterate, "to me." After reading many reviews I saw that a lot of people liked it, and, even though I didn't, I decided that since that is the way it is, I would just adapt and learn to like it. I did learn to adapt, but it wasn't easy.
I'll stop now, before I create 10 pages in the forum with just this one post.