It’s a minor trade off. Going just under bottom cp makes your dudes much more durable and able to take down large number of defenders in one go. You can also “save” guys on intelligent switching and whatnot.
For the max esteem, though, your pretty much running all your guys to death. So, it can be more item intensive.
But, speed. Also, I’d the gym goes dumb Mon, dumb mon, blissey, or something like that, max esteeming the dumb mons and running from the blissey is the best way to go.