I don't know, I've seen some damned fine 'paintings' done digitally that if I hadn't been looking at a book about digital paintings, I would have never had a clue it wasn't real oil/acrylic/watercolor/etc.
Now, let's not jump the gun here. I said "most." I too have seen some great digital paintings, and I'm not bashing the format. But, as an example, let's have a look at the close up from the second link in the OP. To me the horse looks copy/pasted onto the grass. Careful blending with still wet paint could have made that seamless. Again, OP I love the pic. I'm just pointing out what my eye gravitates to in "most" of these digital paintings.
Edit:
Sorry Sept... just re-read your
entire post that I quoted.
My our point still stands though.