A popular mechanic in games is the drive to collect sets of items that help you progress or score more points. Sometimes this collecting is achieve by exploring the game world, while othertimes your collections are something you choose to bring into a round that help your character progress.
This can be collecting for deck-building, drafting items to gain an advantage, bluffing other players to get the cards you need, or the classic trick-making games. However collecting is used in these games, it offers a way to progress and the satisfaction of brining order to chaos.