I don't mind if the bitcoin dumps as long as i am holding my winnings in bitcoin.
The main problem in gambling is that you have a lot of risk of losing your money. I have seen people invest their savings and hard earned money in bitcoins and later they lost all the money in gambling.
So its not mainly about your portfolio value in terms of dollars but also the risk involved in gambling is a big con for bitcoin gambling.
You may not that care having your money in bitcoin but come to think of it, like some weeks ago when bitcoin was at $40000, bitcoin dropped back to $19000 today, anyone having like $250 bitcoin on a betting online platform will have less than $250 by now. We all have different opinions about this but it is very annoying for people to lose money, in reality, it is not easy at all. I have preferred to use USDT on any gambling site I use, I will only buy bitcoin back in 2023 when I know the crypto market can not go down much further.
If you don't want to risk the volatility of the assets, you can choose USDT to gamble. However, volatility is not negative at all, sometimes it also gives positive results especially if the market is bullish, right now it's bearish so it's not good to gamble with volatile assets especially if you want to withdraw it right away after you gamble.