Understanding the strength of Burning Pact is instructive, I think: If you draw through your deck quickly, exhausting all of the bad cards from it, you can end up with only your good cards left. That might mean a combo of cards which go infinite, or a few cards which are upgraded and strong for the fight you're in, or some cards which massively increase your Strength... something like that. Burning Pact is one of the simpler cards for that job. It does both halves; it draws through your deck faster, and exhausts a card while it's doing so.
