>>30219097It's somewhat balanced around it.
If you use it, battle most trainers you see and run from most wild Pokemon, you'll only be a little overleveled. Maybe 2-3 levels depending on where you are in the game.
If you use it and battle some wild Pokemon and work on catching them to get different abilities, natures, fill your pokedex, etc. you will get overleveled. It's really annoying. I recommend having a team devoted for messing around with chaining and doing pokedex stuff so you don't get your real team to overleveled.
If you don't use it, you'll get underleveled unless you go out of your way to grind. I turned it off halfway through the game and started having a hard time with later route trainers one shotting my Pokemon. It also wasn't fun doing one of the Totem Pokemon because it was too strong to be able to use any kind of strategy against it. I couldn't get any stat buffs off or status it before my pokemon fainted.
The best way to play imo would be to leave it on and just turn it off once you get overleveled.
