It would depend on your Ecosystem, but here are a few things that the above comments doesn't mention about Nokia (Google's because it's Android One) implementation:
1. The Samsung Calendar app syncs with Outlook tasks. This means your Microsoft To-Do tasks will show up on Calendar widgets and the Always on Display, and the Agenda Widget on the lockscreen. No other calendar app in the store or on other manufacturer does all of that, certainly not the Google Calendar app on the Nokia.
2. Google decided things that you can't change. Samsung offers tools to change behavior on the phone. Google's multiwindow features leaves a lot to be desired. Samsung with their Multistar plugin adds a lot of features to this. Popup windows, ability to have both apps running at the same time (Google's implementation pauses one app when the other is selected), and there are several GoodLock plugins that allow you to change things that many people don't like. For example the Task Switcher plugin can change the multitask view from the new "I want to look like an iPhone" carousel view to back to the previous list view, with a selection for grid view as well. Want to add more buttons to the navbar? The Navstar plugin has your back.
3. Android by Google has no secure folder feature. This is a further encrypted section where you can have stuff put in to hide from the rest of your phone, accessible only by a separate password screen. You can even hide it from the app drawer and can be opened by using a dedicated fingerprint.
4. Android One also doesn't let you alter audio routing, ignoring of Audio Focus, altering the number of steps on volume rocker press, letting to audio apps play at the same time, Allow to control app volume independent of each other, etc. Samsung Sound Assistant does this.
5. Don't know what app is giving you an ad that pops up and covers the lockscreen or homescreen? With other phones you'll have to go through a trial and error finding that out. On Samsung, simply open the Nice Catch plugin, and see commercial history, basically a log of apps which served you ads. It also has a vibration history and toast history, so you can review those pesky sudden vibrations or toast messages that disappear so quickly.
These are just features that AFAIK no third party app can accomplish on a non-Samsung phone. And these to me are big deals. There are more as well, but that would make for an even longer post. Sure some may call these bloat, but to me these vastly improve my Android experience in a way no other manufacturer can. Maybe later when Google inevitably copies some of these features for native Android.