>>57268461A good Mimikyu will average a higher quantity of berries over a BFS Gengar or Banette. Also because it's actually berries instead of straight power, those berries scale with level in addition to potentially providing more power per berry based on teammates' types.
In this image for example, what's important is to look at the number of berries gathered, plus the number given by the skill. If you're just looking at the power total, then it gets closer if Mimikyu exchanges Skill Trigger S for Berry Finding. And of course the power will increase exponentially when the level limit is increased, whereas the others don't get any further boost from their skill gains.