I've seen a couple people here talk about Fighting resists and things that laugh off PuP damage…in these cases, the point of PuP isn't damage, it's the boost. While there are certain things that take just enough damage from it to turn some would-be 2HKOs into OHKOs on your next turn, its main point is to give MKang a +2. For most intents and purposes it should be thought of like Swords Dance. For some reason people fixate on the fact that it's a non-STAB 40 BP move, which is completely irrelevant unless your name is Ttar or you're a Ghost trying to block it.
As Dragontamer stated, MKang's first order of business is always getting a boost. If there's still a Ghost on the field, MKang shouldn't MEvo on its first turn so it's guaranteed to get at least +1. While not as terrifying as +2, especially in regards to wall breaking, +1 with an effective Choice Band and a high BP STAB with no drawbacks will still wreck anything that's not very bulky. We're diving into Theorymon, but in my experience it hasn't been hard to find something else on your opponent's team that lets you get in another PuP, and then it's GG.
As Dragontamer stated, MKang's first order of business is always getting a boost. If there's still a Ghost on the field, MKang shouldn't MEvo on its first turn so it's guaranteed to get at least +1. While not as terrifying as +2, especially in regards to wall breaking, +1 with an effective Choice Band and a high BP STAB with no drawbacks will still wreck anything that's not very bulky. We're diving into Theorymon, but in my experience it hasn't been hard to find something else on your opponent's team that lets you get in another PuP, and then it's GG.