"Not everyone has those" seems probably a USA-related perspective as people not having ID is a problem there; but in many places in Europe it's normal to assume that everyone does have a valid ID; you're required to get one when you become an adult, you're required to report if it gets lost/stolen so that it gets blocked and replaced. You don't have to have that ID with you, but not having a passport or ID card at all is a misdemeanor. Even homeless drug addicts generally have them because it's necessary for various things e.g. social services.

If someone needs banking services (or, really, any services from anyone) but don't have a proper gov't ID document then would be considered normal to require that the very first thing they'd need to do is to get/replace that ID. And if you have that, then that's all you need for basic banking services.

I'm not proposing that bank accounts are a legal requirement, but rather that access to banking is a legal right.