Open world games mountains: static meshes or painting?

Hi. This is more a discussion rather than a question, so please share your experience.
Usually, in open world games we are use to see mountains. How they are created?
It’s easy to see when the designers use a set of statics meshes (usually rocks and cliffs) or just they paint the height map with layered materials.
Well, assuming that every open world game is built by an external terrain tool like World Machine or Terragen,
we notice that in Skyrim mountains are built by a set of meshes, but is not the same for The Witcher 3.

Skyrim mountains
The Witcher 3 mountains

As far as I know, the best way to achieve the painting in one shot (without doing it manually) is to apply the textures in a way that the colors are blended depending on the inclination (rock, grass, mud usually). In this case the effort is on doing this operation.

Different from this approach, building mountains by a set of static meshes requires doing it manually.

Assuming my observations are not wrong, what do you think about these 2 techniques?
Which one is better or, when is recommended use one instead of another?
What about the weakness and strong points of each of them?

With the “The Elder Scrolls/Fallout style” you can get nice looking mountain with a really low landscape resolution ( meaning better performance).
To get mountains looking as good as in The Witcher 3 video, you need a high resolution landscape and maybe tesselation. Using the landscape means you don’t have to worry about mountain mesh not blendind with you landscape and you have invisible transitions.

The “The Elder Scrolls/Fallout style” is more a limitation of the custom Gamebryo engine they use since Morrowind.
They use tools like the UE4 landscape tools to shape the landscape then add meshes over it while, like you said, to get nice looking mountains/cliffs with the landscape, you have to use heightmap tools like World Machine and this means that you have no control later in the level design (you can’t move a moutain which is made with the landscape shape)