I personally like it because all throughout S.C. Jotaro always uses Star Platinum to hit everything, I can't remember any point where he actually hit something himself, so for me this is a great showing that Jotaro's a badass even without a punch ghost

Jotaro fought by himself when his age was regressed by Alessi, making him temporary lose Star Platinum.
I also think it's cool because it's so unexpected – they start a Stand fight, and then Jotaro simply punches Josuke in the face with no shenanigans.