I know it's fun to be derisive of HS due to the low skill floor and its pay model, but there are indeed nuances when considering what line of play you make, the probability of them having drawn certain cards, and sometimes even calculating lethal. The game is designed to be accessible, not mindless.
As for the question of the deck being cheap, it definitely is. If you even choose to use cash in the first place, it's just $25 bucks to unlock the parts of both adventures you need. If you want to play a top-tier, competitive deck in other tcg, you're looking to spend a lot more than that. It's dirt cheap, relatively speaking.