It's players preference. But for newbie I suggest to play casino game roulette since you are going to pick a color and hope that it would stop at that color, simple right? You can start with that and start exploring with other casino games before jumping to sports betting but if you love sports in the first place I think you can answer that to yourself.
ya.ya.yo!
Why roulette? If the main idea is just to choose between 2 possible results, dice game is better because of lower house edge.
Dice is also simple compared to roulette, I believe dice is better than roulette for newbies.
I prefer sportbetting sites anyway, at least it's more fun and makes your brain work.
Talking about fun, people may have different taste on which game that gives them fun.
Poker is one of casinos games which is fun to play and make your brain work as well.