Checking privileges I noticed that blobstores-create gave delete permission making it indistinguishable (at least from the UI) from blobstores-all.
No other create permission reviewed gives delete so I'm filing for eval.
Blobstore is new for NX3 so is not in NX2. I did not eval older NX3 at this time.
Triage Note: Likely that the UI has the wrong permission.