I can think in 2 direct benefits:
People who likes gambling but are not used to cryptos, will research and learn how to use, and with this we gain popularity
The second is the fact that people have to buy crypto to play games or to bet, and this increase the volume and price of BTC, it's a good thing
Crypto gambling is not really that much adopted at this time even though it gains popularity cause some gamblers are still using fiat rather than of using crypto. Mentioning in some areas where crypto is banned, they will consider fiat if they wanted to gamble.
For the continuous growth of crypto gambling sites, it gradually lifts up the chances that those who are using fiat will soon to welcome crypto in their life. But of course, it will take time and it also depends on how the market moves.