Did OP mention anywhere why they support only BSV but no other cryptocurrencies (on their website or here)? I cannot simply move on when people try to promote/create hype on something which is not at all having real potential. AFAIK BSV is not supporting dapps hence there could not be any justification on sticking only on BSV. Even ETH or TRON dapps based on gambling houses are expanding their business by accepting other cryptos, when this house got nothing do with one particular coin then it makes me to assume like it is all about promoting that coin.
I don't think it is related with dapps or smart contracts. This is related with moneybutton wallets. Thanks to this wallet, a transaction method similar to LN is followed. You can follow this guide on how it works.
https://peergame.com/wallet-guideHowever, as you said, ETH, EOS or TRX dapss would be more useful. Still, if I was going to use a dapps, I would prefer ETH. I am not sure that EOS and TRX networks could achieve the desired success.