Oh, I agree with that in large part-- though I might disagree that it's the market place that has anything to do with judging the artistic "value" of a painting. Beyond that, I agree.
All art is artifice, and that goes both ways. Natural media art is no more "real" than digital art. That's partly why I don't call it "real watercolors" or "watercolors in the real world". It's all the real world.
I'm not against using digital tools to do magic digital things- like mixing media in ways you wouldn't normally be able to do. Look at my self-portrait 2 or 3 pages back. I suppose it's "watercolory", but the truth is that it does all sorts of things we can't really do with natural media watercolors. It's just play.
But I do think interesting art tends to have a feeling of texture and grit to it. There's a lot to be said for the value of seeing two things interact, like a mark-making tool (a pencil, a brush, a crayon) and a surface. As chinapete so astutely observed the other day-- bringing texture and visual grit into your art is interesting to many of us because that technique is reflective of the fact that the world is full of subtly and texture. I like natural media watercolors because I like how aggressively it interacts with paper grain, how the pigment moves and bends to the will of water, how translucent the layers of color are, how you see through it, how soft and ambient a visual can be.
Those are all aesthetic choices that I bring to digital watercolors because they happen to please me regardless of the medium. I don't think it has as much to do with "replicating" natural media watercolors (although much of this thread is couched in that language to help focus conversation), as it does with general aesthetic choices. I'm not really interested in only a "fidelity" to natural media watercolors, like it's a kind of dogma, where, for example, you wouldn't be allowed to do certain things because you couldn't do them with natural media. I'm not interested in that. I'm interested in interesting art. These are just techniques, IMO, to achieve some of those results.
If I'm accused (haha!) of using texture in an interesting way that's reflective of how I see the world, and of laying down my color in a translucent layered manner, than I'm guilty as charged!!
.... Ha! Did I just make my Digital Watercolors Manifesto?