I think casino bets is more risky than sport. Casino bets for experienced gamers it's also most risky betting on online sites. If you see then notice that most of the people lose their cryptocurrency on bets and also gain profit or extra money by betting. On the other side sport is less risky than casino, I read huge post about that and also surfing different kinds of online articles. So based on my information i think casino bets is more risky than sport.
Actually, both casino bets and sports bet has the same risk, we can lose money, but I guess that in the casino bets will have a bigger chance to lose. I think in the sports bet we can minimize the chance of losing by collecting much information for each match, so we have details info to choose the right teams. But still, it depends on you on how much money you will use in each gambling type.