In my experience (UK traditional banking system) I can move money directly A to C at 4am on a weekend, any amount, without talking to anyone for a NO fee. That's just how online banking works, and I'd have to increase the sums of money involved by an order of magnitude or two before having to walk into a bank. What sorts of values of A, C and $ do you have in mind where a bank isn't cheaper, faster and more convenient than crypto?
This is the “works on my machine” of the banking world. Local transfers in the UK work well but if you try to do the same transfer to a non-UK bank account, you will no longer have those same features. This is because each country implements it’s own banking protocols. In crypto, there is a single protocol that all users agree on, and so you can trade ETH, USDC, and other tokens all in the same way regardless of your physical residence.
First your bank can’t move money from A as it doesn’t control A. A and C and services or even my personal wallet, not banks. The point is a bank is not needed to facilitate the transfer.
Instead of having to move money from wallet to bank to stock exchange, money can move directly from wallet to exchange and vice versa, no bank.
