I talked to USDS before and after a couple interviews I got the impression that I'd be engaged in shorter engagements with customers primarily and that I would need to squeeze an engagement into a schedule that wouldn't work for anyone other than 1099 style contractors or those between jobs basically. That's a major part of where my speculation came from that many (or at least some) at USDS are being onboard as contractors because that's pretty much how consulting works classically. While that doesn't mean everyone works that way, it does seem contrary to the evidence that USDS is supposed to be exclusively (presumably, retained, FTE-ish, salaried) feds.
Regardless, I greatly welcome change to the federal service system in any way to promote better retention and progress for its tech workers. Federal service used to mean good and service a source of genuine pride. I went into federal service a long time ago with enthusiasm for change and left pretty damn disillusioned rather quickly.