This belt was once punk, then emo. However, some shottas got a hold of these belts. Now, you can see these belts being worn in the ghetto and by people who probably don't even listen to rock. Some Shottas (and people who follow the shotta style) also use the chains and spikes that were once exclusive to rock. This is probably just the 'in' thing right now, and will pass.
by wrapping it around your hands and knuckles, you can hit people in the face without hurting yourself while still dishing the same damage if not more.