Sports betting is all about finding value bets where you think the bookie is wrong is his assesment of the match/bet line. It seems easy but is really hard and to have a positive ROI year after year, is only given for a couple of people.
And you are right, in a way it is similar to trading, trading seems to be awfully simple as you only need to buy for a low price and sell for a higher one, and despite this apparent simplicity very few people can become profitable long term, and something very similar happens with sports bets, finding value and having a skill slightly above average to pick winners are both necessary, and while in theory this may seem easy it is something that is incredibly hard to do.
Since skills are involved in sports betting, the odds can be used in the player's favor but let's don't forget the house edge %. The house edge % on sports betting especially live betting is very high and bookies usually don't care about the winners since hedging the big positions is possible on main platforms. Hard to achieve the highest ROI in the long term but not impossible, odds are better on bookies than casino platforms, IMHO.