I would like to see concrete stats data, which I doubt we can get, but I believe it does affect, as at least part of the gamblers exchange fiat for bitcoin and other cryptos in order to gamble and the one who exchanged this week now has 25% in fiat equivalent.
In the same way I think that in bull market the opposite happens, people bet more happily because when changing fiat to crypto, after a short time they have already won by the change. They have the feeling of having more money when betting.
An example can be seen here:
I don't know for others but for me personally this has an effect. I am still placing moderate amount of bets but that's in USD value. I always consider the USD value on my bets even if I'm using cryptocurrencies. With the current dips of Bitcoin, the USD value remains but I am somehow affected by how high these bets are in terms of Bitcoin. Before, I could place bets as little as 0.0005 BTC but now it seems it is not enough anymore.
There will be people who don't act this way, but it's clear that at least for some of the gamblers it has an impact.