I'd use one or two of those to secure a motherboard, but not put one in each hole. Using one to hold your heatsink in place would secure the processor, one for the graphics card, one for your expensive BRD drive, one for your hard drive - you get the picture. They sell locking lug nuts for car wheels, but they're not meant to replace every lug nut, just one. Like those, these would make it too tedious to work with your system if you replace EVERY screw with one.

This article is -old- but good point, Victor. :)