I made the same mistake once! I saw familiar teams playing and I placed a bet, only after placing a bet it came to my brain "it was not the right time for that (it was in the morning hours), and then I realized that I placed a bet on some simulated reality game! Well, since then I pay more attention, and I guess you are right that beginners often make this kind of mistake, at least once!
By the way, except LoL, I don't follow and bet on anything else connected with esports! I still like "the old way", betting on real sports, more attractive!
That's a common mistake that a newbie can make because they are completely new to it and they don't have an idea if there are difference between the actual sports bet and the simulated reality games but once get the hang of it they will now realize that the two games are not completely the same.
You must be thankful if you placed your first bet on simulated reality games because you will have an experience with it while others that know sports betting first before this game, will never try betting on it because to them it can look weird and they won't risk money on something that they are not familiar with. If this is not displayed on sports betting site then where should they placed it? But better if they make a category to avoid confusion.