That attack was against the SWIFT system, diverting funds from where they should go. It was not an attack on funds in accounts. The system will be patched.
It also took advantage of a security hole, with an unprotected switch being exploited. That bank should have known better.
But okay, a hacker did get away with millions. Duly noted. I hope he knows how to run, because he'll be on the run for the rest of his life.