Comment by jajko
In Switzerland, almost no bank wants to deal with you if you have US citizenship. Its easier to just avoid creating whole new department for that reporting, risk getting sanctions if you make a mistake etc.
US in this case is a global bully, based on some talks with people involved in such processes also arrogant, very aggressive in enforcement, at the end punishing its own citizens just because they can.
Their choice, but if I or my kids would ever be in the situation of potentially gaining citizenship or green card (that probably won't ever happen, life here is much higher quality overall for people like me), this alone is good enough reason to not do it.
The US is a bully because wealthy people want to live, work with, have assets, or even have citizenship in the US. The US is very business friendly and offers top-tier everything if you have money.
Wealthy people though are accustomed to having their cake and eating it too, so naturally they will try to take as much as they can while giving back as little as they can manage. Their wealth will carry them very far towards this goal, so the US cannot be soft when it comes collecting.