Pack Wars is made up and there are a few different versions of it, but the idea is that your packs are your deck and not that they're your pool. It's a silly, silly format and I feel silly telling you, "You're doing Pack Wars wrong!" but if you're using booster packs as your pool and building a deck out of it, that's a variation on the sealed deck format. Most of the time when I've seen Pack Wars, players try to avoid even looking at their cards before they draw them, since a sort of surprise factor is seen as an aspect of the format.