If your other passport shows you were born in US your bank will still hold you to FATCA controls, and even if it doesn't show that then they're still bound to FATCA and can be punished if it's uncovered you're a US citizen.
So sad.
Reminds me of Elon Musk recently complaining about how hard it is to be a billionaire.
It's hilarious how much Americans would be willing to sabotage themselves if only they could inconvenience the accountant or lawyer of a billionaire.