Jprime

I have a question. Why do i see people use j.K instead of j.S after a dustloop combo? like.. j.D j.D > dash j.K j.D dj.S j.D instead of j.D j.D > dash j.S j.D dj.S j.D ? Is there some sort of benefit? I know j.S is stronger.. but does it create unwanted pushback or something? does j.K come out faster or have more range or something? I'm unsure because I haven't had problems replacing j.K with j.S after a hitconfirm Thanks.