That's not all that clear. The problems QCs could solve regarding crypto are from number theory. That's basically a branch of math that doesn't really describe

That's not all that clear. The problems QCs could solve regarding crypto are from number theory. That's basically a branch of math that doesn't really describe any real-world stuff. Cryptography is as far as I know the only practical application of that stuff. I couldn't think of any implication of "being able to factor large numbers quickly" or "calculating discrete logarithms quickly" that does not relate to cryptography. But I'd be curious if others think these would have any implications beyond "we'll have to get new algorithms into our cryptography".