I don’t do anything involving the PvP version - but I don’t play PvP in any game.
PvE is a bit boring, honestly, but I do like the collection aspect. I keep my pets out with me all the time running around and doing whatever. Just pick a random pet (using that randomize button) and away we go. I do like that (collection).
But the actual battles themselves? If you have the right pets, they are basically “cookbook” minus any RNG.