Exactly. Blockchain-based or not, it's still impossible to win the house. Casinos and online gambling sites are designed to benefit the owner instead of the gambler. Otherwise, casino operators won't be getting any profit at all. For a gambler, it's best to play skill-based games than anything else. Poker or Blackjack are more suitable for obtaining a profit than luck-based games like Dice or Slots. While there's no way you could always win when gambling, skill-based games are much easier to win if you master them in their entirety.
If you make more money than initially invested, it's recommended to stop playing to secure your profit. Otherwise, you'll become greedy resulting in massive losses over the long run. As long as you play safe by never investing more than you're willing to lose, you'll avoid bankruptcy playing gambling games. In the end, there's no secret to gambling other than being patient and doing your due diligence about how it works, etc. We have to accept the fact that the nature of gambling depends more on luck than anything else. Once you do that, you'll be quite successful in this venture. Just my opinion