Regardless, bulky Psychic types run train over the set as is, and it relies on Sucker Punch to hit them--and they very well may not be attacking you, so this is a bit unreliable.
This is where Endeavor comes in, as it brings Musharna down to 1HP. If you have sub up or if they decide to do something dumb like CM, you can easily dispatch them next turn however you like. This allows Kangaskhan to not only hit like a truck with Reversal, it also overcomes it's hardest counters by making them extremely easy to revenge.