Why would a bank require someone to go to a branch to change their phone number? I can change my contact info on the website for all the financial institutions I use.
The branch is the last place where a real person meets another real person. Even that person looks up everything on their terminal, and the whole thing is probably security theater, but I think having at least one physical backstop is a good idea.
My banks require physical presence for stuff like changing phone numbers and nominees. We get OTPs on our phones, so that makes perfect sense.
My mom works at a credit union and the staff are constantly saving people from scams just because the customer came in and the staff had a chance to notice something fishy happening.
I can too, but the difference is that I'm also not the Pope. Someone supplanting the identity of some rando is a negligible risk for the bank compared to supplanting the Pope.