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