It's not in the best interest of the usually seen computer viruses to brick a computer this way. A bricked computer cannot be turned into a spam zombie or a node in a botnet.

However, considering the implications of Stuxnet, I can see a lot of uses for processor kill switches. Imagine not only having to replace all your centrifuges, you also have to replace all desktop computers in your government offices, as well as the servers running your supply chains. To make it more interesting, try to do that during an invasion.

To be fair, you may want to brick a stolen computer, but that only guarantees it will never show up on any authorized dealer who can check the serial number against a list of stolen computers.