it's slower and harder
i don't get how running then pushing jump/z at the same time is easier in terms of input than run > push down > either shield grab or wait for the animation of crouching to end so you grab which is a lot more complicated and pointless. if you can explain how it's easier then be my guest, but it doesn't seem like there is a way in which that becomes easier
and btw, it's not dash attack canceling, it's just dash canceling (which you see with running dsmash with peach)
Wait, are you saying that JC grabs are easier than dash canceled ones, or harder? I'm making the point that dash canceled ones are easier, and it sounds like you're saying they aren't, but your post confuses me a little.
But this is my rationale:
For JC grabs, you have to run, and push a jump button at the same time as Z, correct? In my mind, at least, I find that getting that jump button input (whether it be up on the control stick or X/Y) is difficult to do after running. Since the point of a JC grab is grab out of a run while retaining your standing grab (if it isn't, please feel free to correct me), I figure that you can just run, press down on the control stick, and then grab, with having to press a jump button, and then have the risk of jumping.
A dash cancelled grab gives you the same effect as a JC grab, but with easier input. And your right, it is dash cancelling, I don't know why I typed dash attack cancelling...
EDIT: After testing it out in Training mode, it seems that for quick grabs over short distances, JC grabbing works better than dash cancelling them. The input issue I was talking about doesn't really seem to make a difference after testing it out. As for longer distances, it doesn't really matter as much. So...guess I wasted all this time, then.