For my workflow, it makes it easier to use the clothing - a little bit of work at the front end saves me hours on the back end.

Once one moves away from single character still images, one has to move away from a Poser 4 workflow and enter the 21st century. In Poser, one can easily decouple clothing from the figure it was designed for originally. If I slip Dawn, Pauline, or Sydney into a V4 outfit (And I have dozens of V4 outfits that have never been worn by V4), those V4 morphs are just hogging memory.

It also becomes necessary if you want to have a group scene. It is much easier to deal with a fully clothed figures in the 20 - 50Mb range than in the 1Gb range.

Poser gets a bit unresponsive once it goes past 6Gb in memory (On OSX). I used to hit that pretty regularly with 3 or 4 fully clothed figures. A Star Trek TOS Enterprise bridge has 13 positions to man. At 1 point I had 8 different bridges, based on camera angle, because I simply couldn't load all of the figures in a scene.

Even when there is only 1 character in the scene, I have found it necessary for the following reasons:

1. Conforming clothing NEVER has all of the morphs that come with dial-spun characters. If the character is a custom morph (and I have a number of those), then the chances of the FBM being in the clothing is 0, unless the clothing vendor made the character.
2. Conforming clothing never has any 3rd party morph sets.
3. It makes it easier to move the clothing from 1 base mesh to another, as mentioned earlier.
4. For me, characters as purchased, are a starting point not an end point. I adjust every figure, usually scaling back the size overall, and the boobage to where it actually matches real people.
5. Loading 500Mb of morphs into each piece of clothing can be a nightmare (example - add a morph that is already in the clothing and it never works again.)

It is about being productive - Not to mention the fact that the content takes up much less space in the runtime.