Its only possible because of Ethereum and the Blockchain.
Trustless gambling can be done in bitcoin as well, although it's kind of awkward. I have worked through the logic of how to do a trustless 50% win, 50% lose bet (with arbitrary payouts) on a napkin, and believe it would work
Nobody touches your money. You dont have to trust anybody with your money. Its just you and the Smart Contract. We believe this is the future of gambling.
If so, it doesn't sound like a future I'd want to invest in. If it's trustless, there's no need for reputation, and if it's a smart contract it can be trivially duplicated.
I however think the biggest issues are going to be UX ones, it's going to be hard to complete with the sleek experience offered by gambling sites when you are interacting with a smart contract, and waiting on blocks (even if they're every 10 seconds)