Quote - Most UV mapping apps and modelling programs that do UV mapping can generate UV coordinates outside of [0, 1].
Poser will read these and makes them available in the material room which is useful for some procedural materials.

Yeah, I'm concerned mostly about models I want to use in Lightwave, ZBrush and Poser. LightWave and Poser obviously both can handle OBJ files with overlapping UVs since they treat materials separately, but ZBrush has fits over the idea. So if I want to model stuff that I can use in all apps, I need to either settle for some materials having very small relative spaces in the UV map, or use multiple regions.
Being able to use multiple regions is a much better answer, IMO, because then I can have parts taking up an entire UV "square" and not have to use ridiculously huge image maps to get good detail into them.