I was thinking about this (while drawing), and there's a few points to make:
* There's meaning in all the little marks. Drawings are potentially layered with meaning. I was drawing a stick I found in the park, and thinking: this is the extent and the way in which the stick is straight or curved, and the specific way and form that it's knobbly, and that's all explained by how it grew; this green on it is the peculiar blue-green of lichen; it's a oak stick, I like oak; my drawing is just a stick, good, I might frame it, call it anti-art maybe. Some or all of that is expressed in the marks, though this becomes more apparent if I tell you that it is.
* So, an AI - diffusion - could undoubtedly draw a stick in an arty way. But to draw one that fits the above meanings, it has to be prompted with the meaning. The AI can't prompt itself, so there's a role for artist-as-prompt-writer. Whoopee, right, what fun. These prompts, if about graphical matters and a sort of meditation on the stick, would be essentially lies, because no such exploration of the form and significance of the stick would have really taken place without trying to draw it. It can't prompt itself or be honest.
* So to come up with the above words that might do as a prompt, I had to draw a stick. I had to learn by drawing a stick, even though I've been drawing for decades. Experience isn't the whole deal, otherwise the artist is only churning out filler material, which would be like AI art. Instead the artist has to explore all the time, while leaning on experience. The viewers are into that, they sense the excitement of exploration. They want to see an artist. Well, not exactly, most artists are unrewarding to look at (Brian Froud for instance), but they want to see creativity unfolding, over several pictures.
You can have non-graphical (non-mark-making) prompt-art, a bit like collage or photography, sure, but that's its own thing. Like you're saying, you can't just fake the craft forever, and even faking it once is less than ideal, unless you're narrowly focussed on output that meets targets, instead of meaning.
With programming, this might be different, since hitting targets and getting functionality might be all that's wanted, but I'm sure it depends.