It also depends on what you're trying to do.

If you're using Wardrobe Wizard already, WW will convert to a morphed figure if you're just trying to get clothing on a supported customized figure. There's not much advantage to injecting a bunch of body morphs into a clothing item that you're using for yourself because it just bulks up the vertex count for the clothing figure and stresses Poser by eating up resources. If you're releasing the item for others to use, then adding morphs is useful because it adds flexibility to the clothing item for them without their needing WW or other programs.