As far as i know, you can play directly from wallet in luckybit. You just need to copy their address and send it amount which they needed to play/gamble. They have plinko games, so once your deposit come thru them, you can watch your bet
I do no think it is the one asked by OP. As per my understanding, OP is looking for a site where he can play/login using his wallet. There were some sites uses this kind of feature but most of then are ethereum based gambling site where users are able to login using metamask. I myself prefer to avoid such sites because I prefer to use common site where I need to send deposit first to my account instead of connecting my wallet to a gambling site.
your right , this isnt what we look for but we look for site that only enables to import directly out wallet or private keys if other option isnt allowed. these kind of gambling site are etherium based because they are decentralized . usually mostly altcoins and tokens are listed on a decentralized exchange right ? gambling is already risky but importing our private key to an online platform adds another risk. your choice of avoiding them was ok