It's up to you to define "functional" based on your use case. If you are unhappy with the current state of Comaps or other open source map apps, then of course you are free to use Google or Apple.
Edit just to expand somewhat: For what it's worth, I find Comaps great for my use case, so it is more than "funcional" for me. That's what I was getting at.
The internet can be so crass sometimes, it's tiresome