Bitcoin is not stable, and it is digital, and banks don't have control over it. Once the price of Bitcoin drops so much, it will affect banks. Banks wouldn't risk their reputation by holding people's BTC. Maybe they are going to accept money from buyers who deal with someone selling and buying BTC, but I believe they don't want to be involve with this deal because crypto is risky and not stable. Maybe for USDT or any stable coin they might accept, but not for Bitcoin.

However, maybe depends on the jurisdiction since someone above said there are some banks, but here in my country, they don't accept Bitcoin since it is not widely used yet here.