Well-made conforming clothing with lots of morphs and posing handles is great, but still very limited compared to dynamic. You can only use conforming clothing on the figure it was made for. Posing conforming clothing with a lot of morphs is easy, but if you're doing animation, dynamic is still easier. And conforming clothing with a lot of morphs can be a real load on the system resources. Dynamic clothing tends to be lean and mean.

An example of clothing that should have been dynamic: The Dress at DAZ. The way they did it was really klunky, IMO. They made morphs for the dress that matched each of the standard DAZ poses that come with V3 or SP (depending on which figure the dress was for). Sure, it looked great and was easy, but it's awfully limiting.