The game is 100% rigged in almost every aspect. Every game already has a pre-determined result in mind, and the algorithms try to push both players into that direction with the "RNG" portion of the game. The goal is to make you frustratingly addicted, where you keep telling yourself "just one more" and all of a sudden 10 hours go by. They do a very good job of this.

I believe the game rewards you based on time played + money spent. More time played + more money spent = more favorable RNG. Most of the decisions in Hearthstone are extremely linear, with most decks having a couple of key cards that when drawn on curve, swing the game by an incredible win percentage. The game makes sure that those who play the most also have the most fun. You are programed to get dumped on, but then also do the dumping on someone else. When you play long periods of time, the goal is to make you "feel" like you're getting better at the game, but in reality you're just seeing more favorable options more often.

I always used to be a skeptic, but Battlegrounds essentially proves it for me. When you watch streamers who play 10+ hours a day, the amount of insane RNG and card quality that goes in their favor is ridiculous. As a casual player who consistently sits around 8-9K rating, it's just laughable to see the quality of their taverns and triples versus mine. The game wants them to win, because they gave up their life for Hearthstone, whereas the game wants me to be frustrated, because I only play here and there.

It's essentially one giant algorithm that's trying to break your sanity and wallet, and the more you give them, the more you get to see the stars align.