That’s easy: safety and regulation.

I am happy for the bank to control the code which determines how my money moves, because bugs are a thing, all code has bugs, and if the code that moves my money has bugs, the bank is responsible and I get my money back.

I’m happy for my bank to control the interface, because fraud is a thing and the interfaces they offer are sufficient for my needs. Besides, my real money management is in financial planning, and I have spreadsheets under my own control for that.

I’m happy for the bank to enact restrictions (imposed by my government) on where I send my money because global politics are a thing and monetary sanctions are a powerful alternative to war.

In short, the benefits of centralized control have far outweighed the negatives.