Are you saying there's nothing new in this or that it's building on an already established approach? I think the latter is not something anyone is trying to hide - while the former doesn't seem correct.
What’s new in the paper is the technique to generate the gaussians from photos. The output that is used to render uses a technique that is a decade or three old, but not terribly practical until recently.
For me, a rendering guy, that’s great! The data used at render time is very simple and flexible. Simpler than triangles even when you get into non-trivial operations.
The view-dependent bit reflects the simplicity of the data. The data is similar to an oriented, stretchy box that you interpret as an oriented, stretchy, fuzzy ball (the Gaussian field). What you do from there is up to you.
Classically, researchers were interested in just using the splats at all. So, they just assigned a single color to each one.
This paper assigns a spherical harmonic-based color sphere instead. That gives it the view angle -> color function.
There is a second paper focused on moving splats. It just uses solid colored splats.
You could instead associate albedo/specular/roughness from real time materials and do real time lighting. But, you’d have to figure out how to generate/capture those values.
For me, a rendering guy, that’s great! The data used at render time is very simple and flexible. Simpler than triangles even when you get into non-trivial operations.