That's true for passwords (where you don't really use raw SHA or something, but rather something like bcrypt which is intentionally slow), not necessarily for a

That's true for passwords (where you don't really use raw SHA or something, but rather something like bcrypt which is intentionally slow), not necessarily for all uses of passwords. E.g. computing a SHA sum of some binary doesn't need to be slow, it just has to be practically impossible to create a collision (which is what's required of every good cryptographic hash function).