the most is fuzzy guard , or to cancel a laggy j.hs move like pot.
a good example is this, ky knocks you down at the corner with his 236k. He does 236D frc and does j.s .Here has 2 parts to what he can do
Part1- after j.s , he does j.s j.hs and you have to block high
part2 - after j.s , he lands and does c.s k his fast and good low. Block low =/ mix up FTW
I believe you know the advantages of doing j.s very close to the ground right? ;o