I think this is where insurance companies generally pop up as a solution. I.e. the same solution as with regular bank accounts. Layering humans on top of algorithms makes sense.

We already have SWIFT and networks layered under humans in the fiat system, so now we're just pushing more complex algorithms. In the case of block chains, I'd say the concept of asymmetric cryptography is an improvement over mutual trust in secure backoffice communication channels.

I'm not into crypto (still thinking it's a solution waiting for a problem), but arguing that banks can do reversals isn't fair. Someone moving fiat quickly between banks will make it hard to reverse as well. I can't imagine a bank is going to just say "I guess they stole it from you, transferred it to us, but then withdrew from us. Let me go ahead and reimburse you anyway." That smells like a insurance case, no matter the underlying algorithms.