peterb
You can - but Microsoft are lagging behind Apple and Android - at the moment, and I'm not convinced that their ecosystem is as well developed as Apple's or Google's, but as you say, if MS can integrate with Googles system, and that is what you want to do, it is a possible alternative.
It's a bit of weird one for me, when I look at my usage of google things (outside of android itself) I only really use search and play music, but even that is more of a case of backing up my music for free versus the player side of things. I don't use gmail, even though I have an account and I don't use their office stuff either.
Compared with MS where I use office, onedrive and hotmail (for places where junk mail will turn up and forums). I also spend more considerably more time on windows than I do Android too, even in my ‘spare time’, I even use a few of MS's apps on android because their offerings are better or sync better with my home/work setup. Bing in most cases though is absolutely useless, but some aspects of cortana are actually minimally useful at least on the pc.
But like you say it really is a case of what you actually want to use your phone for and as I don't use my phone for instagram and the likes because mines more for ‘work’ and general communication via phone or text so I don't need things like instagram. I could happily get away with a windows mobile device but sadly the choices are currently a bit limited and the older offerings weren't really that compelling so I went android and will likely stay with it for the time being… unless the fabled surface phone comes out, that may make me want to switch lol