For me it isn't better overall performance, but better radio reception and wifi signal strength specifically.Everyone's claiming/stating that newer MCU=better performances, do any of you have ever read a changelog file of these new MCU?No, because these file logs simply do not exist so your statements are based on personal impression only.
The wifi signal strength alone is something that would force me to keep the updated MCU.
I am not disregarding your concern as my knowledge of MCU's is simply that I know how to update them and know how to roll back to an older version, so do appreciate the fact that you have highlighted a possible reason not to update. But so far, there is no real reason for me to doubt @typos1 as his explanation sounds right to me.