I don’t use web3 wallet because I’m playing with Bitcoin sent directly from Electrum but that doesn’t mean I shouldn’t play here because I don’t use web3 wallet.
You don't have to login to the website using your email address even if you want to play with bitcoin.
You can create an empty wallet on Metamask, connect your wallet to metawin and then deposit bitcoin to your custodial wallet.
Maybe the casino he alternatively used is not really implementing 100% the web3 feature on their casino since base on his claims there's still a log in feature on that casino.
But in Metawin they can simply do what you have been said and that would be the most easiest way for people to gamble without getting any much hassle just like signing up an account before you can enter their casino.
Anyways everything is good since for sure as he or we play on metawin we could really see how convenient the web3 feature for us gamblers.