Devil's advocate, right here. Paint me a target.
Don't know that I could defend anyone for owning one of these just to annotate/ write words down when a stylus is $5 on Monoprice, but as a digital artist who's been deferring gratification with quiet glee for years, watching the pricing of magical drawable screens drift slowly down from the $3000 Cintiq from Wacom a decade ago to the cost of a middle-of-the-line tablet and a pressure sensitive stylus...
I can actually see myself indulging on this one, in a year or so, assuming the reviews bear out and this pressure-sensitive iPane they're suggesting isn't exceptionally fragile. The marketing language makes me a little ill, but back when I was getting paid for graphics, digital artist meant Mac user, so I long ago learned when to pinch my nose, open my wallet, and enjoy the splendor.
Sure, watercolors are cheaper, but clay is cheaper than marble. It depends on whether you love painting with light over pigment and what you mean to do with the result - I like the ability to give it away and keep it at the same time.