Pockets are nice, but can they hold a bottle of beer? Generally no, preventing them from achieving carrying-device greatness. Holster Up! Drink Holders, on the other hand, carry the most important things: credit/ID cards, cash, and, of course, beer. Your move, pockets.
Founded back in the days of the wild west, a group of renegade cowboys were on a mission rustling up some cattle. It was a hot day, and they wanted a drink of sarsaparilla. How were they supposed to rustle their cattle AND have sarsaparilla at the same time, though? Answer: Holster Up!