UDIM UV is a new Feature in CC, tha was create extra for the Character , because it was hard to paint over multiple Material IDs in Substance Painter.
There is a Feedback tracker for suggestions.
If it is for your important to design Cloth with UDIM UV Layout ,you can make a request.
For my purpose I don't need UDIMS for Cloth making and Texturing in Substance Painter, but I would vote as support for you.
Is this on purpose, to keep us buying their super overpriced "packs" of clothing (much of which just doesn't look as cool as what I can find for MD?)...
What has the cool looking with a UV map to do ?
The Mesh and Texturing is skill Level and not a UDIM Layout UV map thing