I have many stories about that actually, using my phone for solutions/automations working with servers, paperwork, exchanging-syncing huge amounts off data, remote controls, photo/video/audio/asset/ editing-checking, POS/site managing etc, but that's too much to talk about!
My point is, there are many things that can be done with a good android phone if you do your research and implement it right!
Other than that, personally I don't believe in "all in one" solutions in general. There is a usage scenario for a phone, a mac, a laptop/pc, a tablet etc and nothing can completely replace the other.
That's why I always change my "tech" setup according to my needs thought the year. I combine whatever makes my life easier at that time and move on with my life: )