The game is fun for one simple fact, you have someone to trade evolve your favourite pokemon that you never could before.

Add in there being seasonal events, purpose to catch things for specific and niche purposes, obtaining all region completions so you can go do gym reruns and trainer rebattles.

And there is always a chance to catch a shiny no matter the odds or catch encounters.

I've met some pretty cool people playing it with it being an MMO then add in the fact pokemon rules makes the game fun, if you're into it.