Some questions are not about payments at all. Most scholars of Islamic law treat gambling as forbidden whatever the currency, so paying in crypto does not make a casino halal. Legality depends on where the player lives, and many crypto casinos hold a licence from a single offshore regulator or none, which leaves little recourse in a dispute. Checking the licence, the terms for withdrawals and the coins accepted before depositing avoids most of the problems players report.
Crypto casinos are popular for fast payouts, fewer banking steps and the privacy some players want. Whether bitcoin gambling is worth it is a different question, because the coin itself adds risk: a win can shrink before it is sold, and a loss can grow if the price rises afterwards. Holding crypto is investing, staking it at a casino is gambling, and frequent crypto trading on short price moves behaves much more like gambling than many traders accept.
Stablecoins such as USDT are popular for gambling because their value tracks a traditional currency, so a balance does not swing with the crypto market. To pay with USDT, a player copies the casino's deposit address for the right network and sends from a wallet or exchange; choosing the wrong network can lose the funds. To cash out USDT, the player requests a withdrawal to their own address and can then sell it on an exchange for local money.