Much like the Keynes quote about sound bankers, a safe bank customer is not one who doesn't get hacked, but one who gets hacked in the same way at the same time as everyone else. So no, I don't worry about doing something "unsafe" with my bank details as long as it's something mainstream that everyone else is doing. If it goes wrong, the government will bail me out. It can't be less safe than paper cheques, which apparently the US still uses.