I haven’t used vertex painting in a very long while, but it’s definitely something I should remember to consider (on top of all the other features I’ve yet to explore/exhaust within Blender).
The end result for this image comes from some procedural cloud color texture and local lighting.
the reason I thought that is because it looks to have a subtle emit value which can be texture based, but can also be faked with ‘vertex color light’. I haven’t really used it much but it’s a cool effect. So many things that blender can do.