That's a pretty low bar. To be a net benefit it should emit less carbon than traditional payment processing. If you set my house on fire you don't get to call saving my cat a "net benefit".
I don’t think you understand what “net benefit” means. It does not mean “the most optimal state”, it only means “better than the status quo”. In this case, the status quo for crypto is compute-based, so storage-based crypto is a net benefit if it beats compute-based crypto. Saying something is a net benefit doesn’t imply that it is optimal, so I’m specifically not suggesting that storage based crypto is optimal (indeed, I’m not even sure it is a net benefit; I only said “if it emits less carbon, then it very likely is a net benefit”).