Both type of gambling are equally risky. It depends on the amount you are wagering on the game. No matter what type of gambling you are playing, the results are difficult if not impossible to predict.
You can try to analyse sports gambling but you will not get it right 100% of the time.
Both are at risk. But we certainly know that casinos are impossible for us to at least imagine which ones would benefit us. Everything is 100% dependent on luck. While in sport betting we can enlarge our chances to win. Sport betting is never 100% dependent on luck because we can analyze it first.