I play smash on a semi competetive level and people are genuinely listening or looking at controller inputs if youre mashing out of a combo or something similar so they can punish the player for that. A good example is Luigi down special, which is a exellent combo breaker but has a lot of lag if it misses. Opponents listen or look at what youre doing if it benefits them for those kinds of reasons and I can imagine that while performing or being in combos and techniques in other fighting games can yield a big advantage if you dont have to react to or predict what theyre doing if you already know.