Most people seem to be assuming the intent is either to damage the centrifuges or stop them from working in other obvious ways. However, that would just lead to

Most people seem to be assuming the intent is either to damage the centrifuges or stop them from working in other obvious ways. However, that would just lead to them being replaced, probably with better protection from reinfection. I think there is another option: these modifications in the frequencies were intended to make sure the uranium did not becoming pure enough, effectively preventing Iran from obtaining a working bomb. If the virus wasn't discovered, it could have taken the Iranian scientists years to figure out why the centrifuges weren't doing their jobs, after discovering the lack of purity in the first place.