> Third - we just take a big smelly dump on the teamwork - it's easier and cheaper to let one developer drive the whole change from backend to frontend, despite there are (or were) two different teams - one for FE, one for BE.

Agree with your other points, but IMO this one has always been better. You often need to design the backend and frontend to work with each other, and that requires a lot more coordination when it's separate teams.