It would be a mistake to dismiss these watches, or any other Porsche Design product, as some kind of licensed car-guy accessory.
Porsche Design has always been a separate entity. It was founded in 1970 by Ferdinand Alexander Porsche after the Porsche family stepped down (as they say) from day to day operations of the car company. Ferdinand had served as head of design up to that point and was pretty good at it--he's the guy who designed and developed the Porsche 911 we all know and love today.
Having left the company, and now with time on his hands and (one assumes) plenty of cash, Ferdinand founded Porsche Design as a way to channel his interest and passion for design into all things not cars. So yes, the watches, computers, sunglasses, pipes, luggage and lots of other stuff he designs, all have the Porsche name on them--but they are not licensed, car-guy products (like those cheesy BMW watches that keep showing up here).
All that said, there is at least one connection between the two companies where watches are concerned--the Porsche car company has committed to buying 20 Porsche Design watches each year to reward and recognize the service of it's long-time employees. In other words, if you retire from Porsche, you only get a watch--not a Carrera.
--those cheap bastards!