From general observations:
We get more from Destin than PC. Even those that prefer the busier spots to the East and West like to venture down Scenic 30-A for a day of sightseeing, shopping, dining, and real estate looking. I would bet that it's mostly folks who are on vacation for more than a few days.
I know that the Red Bar brings in people from both Destin and PC, it has become one of those "must go to", or "must go every time we're there" spots.
Rosemary Beach, Seaside, WaterColor, and Grayton, are places that generate a lot of curiosity - add Alys Beach to that list soon. People say the Emerald Coast is the American Riviera. I say SoWal is like the American Cinque Terra (on the Italian Riviera), with scenic villages connected by a trail, ours being a bike trail rather than a hiking trail.
Ultimately, it's the uniqueness and beauty of a condensed area (Scenic 30-A or the Cinque Terra) that is the true attraction.