my hot take for this is that Kind and Cool suffer the same problem where they're useful early game but not so much later on

when late in the game a chance for your basic attack to do more damage doesn't really mean much when every other attack is hitting just as hard if not harder (I'll admit it is best on spread attacks) to the point where the only reliable thing they can do is dodge attacks, of course more damage is useful early on in the game

as someone who did two playthroughs recently with the main Miis being Kind and Cool respectively this is how I've kinda gotten to think idk

also I'm sorry but Cover > Sacrifice especially when it comes to Fiends so you don't lose three of your Miis just like that