USD supports literally any kind of asset.
Here i show you the feature of Character Creator, which is already there.
You can export a character including several motion files.
So this is how the files go into Omniverse:
Where to set the actual motion that is used:
But in iClone, you can only export the character with one single animation.
The conclusion for me is that it is possible to send motion-only data to Omniverse.
And it makes sense.
The question is why iClone doesn't have that option.
As a side note, i recall that 3DXchange has an "motion only" feature for FBX export.
This is not available in Clone 8 as well.
Finally it seems that RL devs don't think this is a needed feature at all...
PS: i created a Feedback Tracker issue a while ago:
https://www.reallusion.com/FeedBackTracker/Issue/iClone-needs-an-motion-only-option-for-FBX-export