....The fact is that you don't need a nuclear warhead. An EMP generator can be constructed that would fit inside a briefcase. If someone had a mind to use such a device, you could merely walk past an unprotected facility such as a server farm or communications center and disrupt the electronics.
Another benefit of EMP hardening, which is considerably more practical, is that it can protect electronic equipment against the effects of lightning and everyday power-line surges.