There are probably only a few casinos now that offer free withdrawals, but I don’t really see it as a big issue as long as the fees aren’t overcharged like some exchanges do.
Especially with Bitcoin, network fees are pretty cheap now, so paying something like 0.001 BTC for a withdrawal would be way too much. I’ve heard exchanges charge that before. With casinos though, I usually gamble using USDT, and the fees are just around $1, which is very reasonable.