You can certainly have instant funds transfers, if you are comfortable with a single security lapse instantly leading to the loss of your life savings. I'd ima

You can certainly have instant funds transfers, if you are comfortable with a single security lapse instantly leading to the loss of your life savings. I'd imagine international transfers are slower proportional to the risk of security lapses when working with disparate organizations (and the difficulty in reversing mistakes.) Blockchains might be more secure in principle than traditional banks, but blockchains are pretty much all designed so that a single key compromise amounts to a catastrophic failure. Now you can manage this by having manu wallets and many keys to some extent, but at the end of the day it's still much less reliable than just having a bunch of bankers who are paid to take their time and ensure sure all transfers are authorized.