Can planar or surface tracker be used to create a 3D scene?

I have a clip that seems easy to 3D track since it's a simple pan of a guy at the top of a short hill falling down the hill and ending up on the ground, with the camera following him (sorry, I can't post the footage since it's not mine). I thought it would be easy to track, it even has a small area that can be seen from start to end.

But first I tried it in Blender, then in Fusion, and no dice. At least with the 3D camera tracker. But today I was playing around with the planar tracker, and also the surface tracker. And in both, after setting a plane with four points that are basically the landslide, they track pretty well.

Since I don't have a lot of time and I'd rather not go down a rabbit hole, I would like to ask you guys, is it worth my time to look into tutorials for any of these trackers? I mean, is it even possible to use them to create a 3D scene, or combine them in any way with the 3D camera tracker to create a good solve?

If the tracks from them are really good, you could consider using those trackers to project a plane with actual trackermakers into your scene and use that to 3D track with recognizable features. No idea if it would work, but apart from that there's no way - currently - to reliably go from these kind of tracks to a full 3D scene.

You could try using a mask or masks to define the the same area in the Camera Tracker, as you defined in the Planar Tracker.

Can planar or surface tracker be used to create a 3D scene?

Yes. You could use it to composite 3D and 2D elements, since Fusion can work with both quite nicely in the same scene. Depending on what you need. You can create 3D elements or import them and work in a 3D environment in Fusion to light and rotate things and than use planar or surface tracker in 2D to place them in a 2D footage. You can also bring in coordinates from 3D scene to 2D, like if you have light in 3D scene and you need 2D lens flare effect to follow the light source from 3D. You can use Locator 3D node. Or you can use 3D track to translate coordinates to 2D in order to change something. Or position it in 3D. You can also go back and forth with a little effort. You can turn 2D to 3D point and the other way around.

Here are some quick tutorials on the Locator node.

Fusion 6 - Locator

Fusion 6 - Using the 3D Locator in reverse

Davinci Resolve Fusion - Convert 3D points to 2D animation

I have a clip that seems easy to 3D track since it's a simple pan...
But first I tried it in Blender, then in Fusion, and no dice. At least with the 3D camera tracker....

Panning motion where camera doesn't move, only rotates, can not be 3D solved as there is no relative motion between features and thus no way to determine their distance from camera. Nodal pans give you a rotating camera with all the solved features on a sphere surface some distance X away from camera (world sphere). It is still a 3D scene though, so you can still place your geo into it, you just have to place it by eye. Both Fusion and Blender can solve nodal pans.