Why do you think that banks will close? What gives you a reason to say that? Do you know what is a bank? Let me remind you, after all, bank is a place that lets those who have a surplus of money to deposit and borrow it to those who have a deficit of it, i.e. it's a middleman that gives the lender a guarantee of profit despite the fact whether borrower pays money or not.
There are national banks (for example FED) behind the commercial banks, it's a huge system and cryptocurrencies and Binance can't abandon it and take place of it. First of all there is no way that can do it with their possibilities and resources and then - a small change in law and it's enough to stop the entire process + not many people will come to support it cause most of the population don't know about bitcoin or cryptocurrencies and if they know, a high percentage of them think negatively about it.
And stablecoins? They are pure shit, crypto version of USD.