This is fun, and all, but let's understand that these printers are NOT your parents' inkjet.
Most use pigmented inks, not dyes. With the correct papers, the prints are vivid, gorgeous and more stable than conventional lab photos (which is what I think they should be compared with, instead of stone lithos), and certainly more stable than the inkjet prints that most people are cranking out.
If photographers want to sign them and limit the available quantities, I see no harm in it. I don't think we'll see editions of 250,000. (These printers are incredibly slow.)