you are right
the point is regardless if the person is gambling for fun or as a "profession" they'll have to decide if they want to hold btc or usd after gambling
it's not the simplest decision depending on where you are gambling too
many things to consider
Every gambler has different reasons for keeping balances in BTC or USD, but in the category of crypto gamblers will choose BTC regardless of the market price, but some want USD because they don't want the value to decrease when the crypto market declines. But it all depends on individual decisions and more gamblers still hold BTC because it is not for investment so it is not affected by the market price.