I'll be honest... I've gotten into competitive battling in so much as I chase good IV'ed pokemon, train EVs, and play strategies online. Here are my personal pros and cons:
+It is a really quick and easy and fun to pass time battling on Wi-Fi.
+It gives you a better insight into moves and strategies you'd never use before.
+You get a better understanding and insight into individual pokemon and what their real strengths and weaknsesses are.
-My actual enjoyment of the games has decreased dramatically. I don't enjoy just regular playthroughs as much as I used to because my brain is just obsessed with arbitrary nonsense like making sure my attack-oriented pokemon beats pokemon that give it ATK EVs, etc. I honestly miss just naively playing through a game story.
-Playing competitively can be insanely repetitive (seeing the EXACT SAME pokemon and strategies over and over and over again)
-Competitive players tend to be VERY judgmental about how you play (I've heard people say outright that people who play on Wi-Fi don't know anything; others just ignore anyone who ply a tier or a style (like Triples) that they don't care about.
That's just a quick run down of my thoughts, anyway.
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