Any A/B should really be Kemper to Interface versus amp/cab/mic to interface otherwise there is some influence.
I think the proper comparison should be to run up and down the stairs with each amp 100 times. The one that makes you pass out first loses
I think that recording the 2 amps is interesting, but for me, the ability to create a very accurate reproduction with a high level of repeatability from the FOH is the big difference. I have had LOTS of variation from my tube amps from different rooms, mics getting bumped, gremlins, little angles, little demons, and God knows what else making my tube amp FOH sound vary wildly.