Keep track of spending in gambling is kinda hard to do with unstable coins like bitcoin and other altcoin, for example, let say, yesterday, you gambled away 0.01 bitcoin, and at the time of the transaction, 0.91 bitcoin was worth $500 due to the price of bitcoin then, and you already put it on record that you lost $500 in gambling yesterday, and by today, the over all price of bitcoin increase by let's say 15 percent or more, going back to your loss in yesterday's gambling, you know it's no longer $500 you lost, the amount you lost has increased by 15 percent or more due to the increase in price of bitcoin - simply because if you hadn't gambled away the bitcoin but held it, the gains today would have been in your pocket - this example is also the other way round in cases where the price of bitcoin falls instead of increase..
For me, I don't see any confusion in gambling with Bitcoin or any stablecoin, because both are not the same, and as such their gambling record ought not to be the same, and by that I mean, you don't need to gamble with Bitcoin and except to keep your records in a stable currency such as dollar or pounds rather than keeping it in same Btc.
Example:
Imagine you gambled 0.001btc to win 0.01btc and you won the game, you should put in the record that you made a profit of 0.009btc by gambling 0.001, and not get to worry whether the price value of that BTC increases or decreases.