For professional sports gamblers, sport betting is like trading I think because of good analysis and correct predictions which are possible in sports betting unlike normal pure gambling that involves only luck! However even at the end there's always a possibility of twist. I guess the only difference between trading and sports betting is in trading if your prediction is wrong, you have the chance to rectify, but in sports betting, you lose all the funds!
Aside all that it's very good when you don't add a lot of games on your betslip even though they are highly tipped to win the game because the longer the slip the odds of you winning reduces a lot. You shouldn't bet so little money and expect to win big, it rarely works out in the end and a very careful analysis and research always helps so as to know who's playing and who's not.