However, there's one advantage if you bet on an non-familiar sport, you will be force to learn that kind of sport so you won't be at loss anymore the next time you decide to bet on it.
How is this an advantage? Someone could argue that they could just not bet on a non-familiar sport and therefore avoiding that loss.
That's the advantage, you get to learn that sport forcefully because you bet on it without any idea of how it goes. But you're right, if someone doesn't have an idea on how that sport goes, it's best not to lose money and be ignorant of it. Anyway, we're all different and whatever will work for us, we should do it. If we think that it's an advantage to learn something new with these sports that we want to bet then learn it first without having the need to bet on it from the beginning.