Installing a wallet is a one-time process. I can't see the hassle you're talking about - you need a wallet to hold your funds anyway.
And, in fact, MetaMask is available for mobile too. Here's the Google Play link to it. Mobile is the new thing now, PCs are way less used. Mobile phones are taken everywhere with us, so now it's a bad idea to create something for PC that doesn't exist on mobile too. Mobility gives innovation a higher chance of being used due to frequent usage of smartphones.
I don't see where this large inconvenience comes from. Using a decentralized casino would work just like a centralized one, the only difference being the fact that casinos would process bets a little slower. On the other side though, your funds are safe. And I see no point in using a fast casino if your funds are at risk 100% of the time.
Please write this part in any language but gibberish... I don't get a single word out of your message.