Why signup when you can login using your Metamask wallet, I think there's a lot of gambling site already have the web 3.0 interated on their gambling site I think you should visit those such as the Owl.games and Sportsbet.io they already have that in their website.
Huh? When did sportsbet.io had implement web 3.0? I don't see there's an option to login via Metamask, only social media e.g. facebook.
However it's depend on which coin you used to gamble, if you use Bitcoin... there's no way you can connect Bitcoin wallet to the site, you must create an account and send your money to your account. Some people also worried to connect their wallet since a lot hacking events right now.