For me, I usually use bitcoin to my online gambling and some other alt-coins, especially if my favorites sites accept other cryptos. But I'm not only gambling with my bitcoin/ cryptocurrencies. I also bet using fiat money but in the real casino, and to some betting sites that don't accept cryptos.
I think using altcoin is more favourable as even if you lose out it will be that altcoin and not bitcoin which can grow quickly whenever some news come in as this is the king of all coins . Bought everyone has different reason to play with particular coin.