If you can create user-friendly app for betting and it is legal, why would you use blockchain for that instead of just using traditional way? I would bet my ass off that the end-users (gamblers) don't give a crap whether it is on blockchain or not, they just want it to be easy, quick and possibly cheap. And of course trustable. And by latter I don't mean "mathematical proof" trustable, they want brand that they know to trust.