>>17921312Pokemon that have large movepools but either need self support from things like Swords Dance, Substitute, or Protect lose a moveslot so they only have three coverage or utility moveslots to work with. This Pokemon may have a typing that screams for dual stabs, but seriously needs a non-stab for coverage against something that can counter it otherwise.
A good example of a utility mon that has FMSS is Gliscor. It needs EQ to threaten Pokemon out, Substitute and Protect to abuse it's passive healing, and Toxic to break stalls. But it could REALLY use Taunt. That's FMMS.