Gamefreak found out most people had it on and they said for those who don't they found a way to still cater to those people:
"Those who have it turned off want to train one specific Pokemon. We thought: is there a way to achieve that? There is, simply by putting the rest of your Pokémon in the PC."
I guess having access to the PC easily now is good I guess? Still more complicated then just having a damn button to turn it off in the menus but ok.