What is "Difficulty" in Pokemon Unite?

Question

Every Pokemon in Unite has a difficulty, like expert. I feel like it means "ease of use", or something like that, but in my opinion, all Pokemon in Unite are on the same ease of use, with some being flat-out better than others, usually because of movepools. So, what defines a Pokemon's "difficulty"?

Comments

It literally is how easy it is to use that pokemon. Expert difficulty would be “harder” to play effectively than the Novice or Intermediate ones
EDIT: The part where you talk about Pokemon being flat-out better than others is also true, but that doesn’t relate to the difficulty. I use UniteDB for what’s better and what isn’t