Materials Science and Drug Discovery would suddenly become a lot easier, along with financial modelling (of our entire society possibly) and logistics/supply chains.

They would also be much better at training ML and doing pattern recognition.

Basically anything that requires a massively parallel computation on undeterminable states that are only clear in hindsight. They’re really important actually and its only an unfortunate side-effect that the same solution breaks all our cryptography.

(of course: the offensive wings of our defence ministries really enjoy that side-effect)