People wear these devices to give themselves super human powers, and other desirable attributes. Most notable is the ability to travel long distances very quickly.
Other powers include metal-muscles. For instance when a skinny little puerto rican fucktard starts crying because you've slowed way below the speed limit to punish him for his tailgating, he can yell "I'll fuck you up mother fucker and slam his dashboard" without actually getting his teeth punched in.
Guy: "oh, you noticed, I'm flattered..."