I recently ran across a mention of a painting in some art magazine. The painting was by a "monochrome artist" which means some chap who paints canvases all the same color. The bit went on about brushwork and luminous depth and so on, but ultimately, the dude had painted a square of canvas blue. It was a blue square. Anyone sensible knows perfectly well that this thing is a scam. The first couple of these things, sure, some sort of commentary on art or something. Now that we're seen a few monochrome canvases, it's pretty much over, there's not much more to say there. To be fair, it looked quite pretty. I'm sure they're quite nice to look at.
Still, these things remain marketable, so the art world continues to ramble on about brushwork and luminous depths.
Here's an interesting aside, though. It's actually pretty hard to cover a big canvas with a single color. Go ahead and get yourself a 3 foot square canvas and some oil paints. Mix yourself up a pretty color, and start painting. You'll be amazed at how difficult it is to nail that exact color when you go to mix up some more. Getting a blue square that's gently mottled is easy. Getting the thing actually sleek and purely monochrome is tough. Now, for all I know, it's an exercise they do in art school and if you go through a BFA in painting you can pretty much do it, but that doesn't make it easy.
Compare with complex and technically tricky wet chemistry processes. Film, salt prints, wet plate, whatever.
Just because it's technically challenging doesn't mean it's good. What makes it good is being good.