I would be happy to use Solana coins to deposit gambling sites, but unfortunately I have not met any site that would support SOL. In my opinion using ETH or BTC for deposit is a kind of charity for miners pocket since even wire transfer appears to be cheaper nowadays.
Solana is very interesting moreover with also very lower transaction fee.' However, this network is still newly very popular and attract so many interests from many parties. that is why gambling sites may still consider about using this.
Moreover they also have other options instead of ERC20, they are likely Tron, XRP, Doge, and also BSC
They commonly have lower transaction fees.
However, ensure that you must choose the right network because once you are wrong, your coins may be lost.