Are you sure WhatsApp would work? I see UWP or chrome wrappers of WhatsApp Web but that relies on having a native app running on your phone for it to communicate with, since everything is tied to your phone number.
Did they ever fix it so that it uses the compass to tell which direction you're facing? That's pretty basic functionality that really should be working by now.
Re: Lumia 520, 720, 920, 1020, 1320 Owners
Microsoft isn't going to get anywhere by being "no worse" than Android. This could have been a selling point for them but they blew it.
The only time I ever see mention of the total numbers of apps in the various stores is when people are making excuses for the shoddy state of the Windows store. I doubt the raw number is much of a selling point either way.