Just because something can be forged doesn't mean it's useless. Signature in isolation doesn't mean anything, the surrounding legal environment is what gives it its powers. That legal environment doesn't operate on boolean logic, but on probability theory. Signature is just an input to that.
Agreed, rules exist for a reason, and good changes are planned and executed safely over time..
But there's still a delta of time during which old rules continue to be applied in a manner that can feel senseless, while new processes are figured out. :-)
