Less gravity losses is another advantage, that's true.
I think it'd be interesting to see a breakdown of that 10% improvement number. Hot staging in and of itself resulting in a 10% additional payload capacity seems large enough that I feel it's rather odd that it isn't more commonly used. I'm curious how much of it is due to "direct" improvements from reduced gravity losses and how much is due to "indirect" improvements like (maybe?) not needing to save as much fuel for boostback.
A comparison against what a "Saturn-style" staging that uses ullage motors might achieve could make for a fun addition as well.