What math can do is help in EV+ games to make predictions but in EV- games its a waste of time trying to develop strategies because every strategy will fail in the long term.
I guess a popular game like poker can be called as EV+ game, right?
I also believe that sports betting is considered an EV+ game as even though the fair odds would normally reduce your wining to 5-10% because of juice but you have the option to increase your odds by selling points.
I like sports but not so with poker and although it's an EV+ game but still I am not winning consistently, so how much more in EV- games?