I'm not sure how to evaluate the question of whether it could do the Fizz Buzz algorithm. Could it run fizzbuzz.c? No, it doesn't have an OS. Could it perform a sequence of operations isomorphic to "count to 100 by 3s and 5s"? It sounds like Aaronson's answer would be yes, but I think you'll be skeptical (and I am too) about whether that really means anything.