>>52830206PSS wasn't just for battling for starters, so I'm not sure why you're even comparing it with showdown
PSS made you feel more connected to the many other people playing Pokemon. If you're a misanthrope, I suppose it's not appealing, but playing the game and getting "NICE"'s from people, and giving strangers O-Powers, leveling up yours was a nice feature. Most importantly it was simple.
And the festival plaza came and made communication completely confusing with mechanics that weren't simplistic at all. They removed essential O-Powers, like capture and hatching, and brought back something similar with Roto Lotto, which is a lottery and thus not as consistent.
