I think Bitkit is at a point where you could use it daily, but that the Lightning Network itself still faces many challenges that will affect self-custodial usage. Every LN payment is a unique situation that can go wrong in many ways.

All complex software has bugs, so use what works for you and submit feedback when you find something off.

Regarding the USA and Phoenix, it probably still works because all they did was remove it from the app store, not block US people (yet?)