Haven't read the thread, but this doesn't seem interesting or controversial. There's two answers:

The institutional degree; or
An image purposefully made by applying paint to a medium.

Seems to capture everything. What obviousness have I missed?

Digital painting is a verb. The product of this action isn't a painting.

Digital painting is a verb. The product of this action isn't a painting. — LuckyR

And yet the softwares have names such as Paint, or Painter, and we refer to the products as digital paintings. Likewise, a cat is a mammal, but some cats are ornaments, cartoons, toys, or jazz musicians.

Digital painting is a verb. The product of this action isn't a painting. — LuckyR

It's a digital painting or just a particular medium. There are many types of paintings, like oil, watercolors, gouache, etc.

Yes, they're called digital paintings specifically to distinguish them from... paintings. Sort of like vegetarian meat.

Ok, that's an interesting example. The words in 'Vegetarian meat' distinguishes the product from meat yet characterizes it as meat because it mimics meat.

Yet we find this combination of words distasteful unlike 'digital painting'. To mimic looks or sounds is harmless, it can be useful even, but something bitter disguised as sweet could kill us. The difference is between our sense organs and their biological functions.

And yet the softwares have names such as Paint, or Painter, and we refer to the products as digital paintings. Likewise, a cat is a mammal, but some cats are ornaments, cartoons, toys, or jazz musicians. — jkop

And then there's CorelDRAW. I made association because the OP post was interested in what distinguishes painting from drawing. If we go by digital metaphors, it seems we associate drawing with lines and painting with filling in colour? A rather shaky hypothesis, but... maybe?

I tend to find colours and textures more significant than lines, regardless of whether the picture is a painting or drawing..But it depends on the context. In architecture lines are more significant. A diagram is plotted with sharp curves or lines, not fat textured brush strokes. Whatever is useful, or interesting, depending on context.

The institutional degree; or
An image purposefully made by applying paint to a medium. — AmadeusD

A painting is an institutional degree??

Under the second definition, iconic caution signage on the freeway would be a painting.

Yes, they're called digital paintings specifically to distinguish them from... paintings. Sort of like vegetarian meat. — LuckyR

"Digital paintings" to distinguish the particular medium of painting.

Vegetarian meat is a poor analogy because both the method of production and consumption are fundamentally different from non-vegetarian meat.

A traditional 'analog' painter can paint digitally using the same fundamentals (shape, value, edge, color, etc). Their style and basic technique could be the same, and the produced work could be practically indistinguishable from their non-digital painting.

A rancher couldn't produce meat in a lab using the same methods they use on a ranch. And they couldn't produce a convincing T-bone steak or chicken thigh with the same nutritional properties as non-synthetic meat.

Vegetarian meat is a poor analogy because both the method of production and consumption are fundamentally different from non-vegetarian meat. — praxis

Method of production maybe, but consumption?

While the technique might be similar in digital vs. Analog painting, the medium of the product couldn't be more different. 1's and 0's, vs paint and canvas. Whereas, vegetarian meat and meat are still ultimately textured protein and fat.

I think the analogy is apt: two categories that neither fully belong to one another, nor are fully distinct. There is no "ultimate answer" to either question: "is a digital painting a painting?", "is vegetarian meat, meat?" The answer is determined by how the categories are defined, nothing more.

Method of production maybe, but consumption? — hypericin

I won't bother to do it but I could post a digital painting and a watercolor painting where you couldn't tell which was which. Your 'consumption' would be the same. The digital could be printed and again your experience would be the same in terms of medium.

About production, what is essential? Using an instrument on a surface to apply marks and forming an image with shape, value, edges, and color.

For synthetic meat to be comparable, it would need to be nearly indistinguishable from meat (like a chicken leg for example) in experience and nutrition. More significantly, the methods used to create it would need to be comparable. A rancher couldn't walk into a lab and produce synthetic meat using the same essential methods they use on a ranch. That's nonsensical.

Uummm... not as similar as you're making it out to be. To my understanding, the skill of mixing paint colors to come up with the exact hue is nothing like clicking on a grid of possible colors, as merely one example.