Theoretically casino bets are more risky than the sport betting. In a dice game the probability of getting a number is very less than what happened in sport betting. And also in a casino game there is a house edge which you can not defeat. But in sport betting there is no such things.
I think, even practically casino bets are more risky than sports bets as most of the casino games involve no type of skill. Almost, every one of them is pure luck. Slots, roulette, and dice have no strategies of winning due to the previous mentioned fact. Even poker player needs good cards if he wants to win and only good luck can bring that to him. Sports bets can be won 90 percent of the time by using analytical skills.
Yes casino games are completely unpredictable games we can not guess those games results. Only our luck will decide we will end with profit or loss. But sports betting is not like that we can predict the games based on our sports knowledge. And here the profit percentage is always high to compare casino games.