I get in a better position to unrack the bar, then my butt gets back on the bench. I use barely any leg drive during my benching. I've focused on it in the past, and I really don't see that much benefit to it. Steve Shaw would agree. Plant feet for stability, get tight, control the weight...everything else is an overcomplication imo.

I understand that the Larsen press (with feet off the ground) variation of benchpress is harder, but I don’t understand why from a kinematics/mechanistic POV… 🤦‍♂️

I understand that the Larsen press (with feet off the ground) variation of benchpress is harder, but I don’t understand why from a kinematics/mechanistic POV… 🤦‍♂️

You are less stable with a feet up bench or larsen press, so it's harder.

I'm pretty sure that lifting your butt off the bench makes the lift a lot easier than keeping it in contact. I do it to unrack because it feels lighter and uses less energy. A lot (maybe most?) of powerlifters do it too, presumably for the same reason. It's also common to see butts coming off the bench when people struggle with the lift.