Learning card counting in Blackjack can be worth it if you're willing to invest the time and effort to master the technique, as it offers a small edge over the casino, usually around 1-2%. However, it's not a guaranteed way to win, as it requires skill, practice, and careful bankroll management. The casino's countermeasures, such as using multiple decks and surveillance, can make it harder to be successful. Additionally, card counting works best in games with fewer decks, which are increasingly rare in many casinos. While it's legal, it can take the fun out of the game, as it requires intense focus, and casinos may ban you if they catch you counting. In the end, it can be profitable over time, but it’s not for everyone, especially if you’re just playing for enjoyment.