I think the same that knowing the game could give you an edge on sports betting.
True, but never underestimate the house since they do plenty of research to make sure that the edge is minimised as much as possible. It's very, very difficult to maintain an edge over the house in the long-term in sports betting.
I consider sports betting as a skilled based type of game, but if a gambler does not have knowledge of the particular sports he is betting, or even just a small knowledge only, then it should not fall to the skilled based classification on his level.
Sports betting does rely on skills, but luck is still involved here. For example, it is possible to lose a 1.01 sure-bet if luck doesn't side with you. Skill based games without luck involved are PvP games etc.
You can't really call 1.01 a sure bet either. In fact, a 1,001 bet is not a sure bet either, the chance that it will go wrong mathematically is about 1 in 1000. If you then place 1000 bets, in theory it will go wrong. But in your mind you start each bet as a favorite with 1 to 1000. There are a few examples of people who have bet on a team that was leading 4-0, and because it went 4-4 they lost a lot of money.