Interesting discussion going on and my take:

1. crypto users are actually Bitcoin users. Agree that more altcoin users are also now betting but you generally find crypto sportsbettors are just using Bitcoin. Not so much because of the tech, but the wider access. Been tempted by smart contract types like ETH and even TRX but the lack of access, wider markets and good odds so far puts me off. Fairlay I like because P2P you can find good odds especially on the longshots.

2. I think the future for crypto users is non-custodial yes, but the future for betting with crypto probably lies in 2nd layer settlements (which even Ethereum is starting to use). Fees for tx is one thing, but I haven't seen smart contract fees lower than $5 since June and if you need 2 smart contracts to place and then claim winnings, it's really not ready yet for betting.