It's must-ish. They have very poor control over their appetites.
A ghoul PC would almost have to be one that has found a way to control said appetite by some special mean then...
Oh, and I just noted this "Inhuman, Supernatural, or Mythic Strength, Speed, Toughness, or Recovery" in the changeling template. I like the fact that there are "gradations" in the "more than human" physical abilities