With me, I used antiair when I have advantage (big collision box, long range attack). For example, I have an idea that compare the size of the char, and if the size is bigger, we may have the advantage over shorter char. Also use antiair actively is not unfair, some char main moveset is that. Just look at Guille from SF, he is zoning char, so it is mainly attack is Sonic Boom, Sonic Boom... until the char jump then a Flash Kick then repeat