Why do guys stockpile coins elsewhere, when they can simply spend them from their wallet daily?

It's simple management, spend them as you can, so too much doesn't build up in your wallet coin pouch. It's likely if wearing a wife beater fits with your character that you do this. Or, if you're metro-ual and you like to look/feel all tight and trim in your garb, and you want only the most minimal sort of wallet,... as with your package perhaps also.