It's good for visualizing something by itself, but not for building a scene out of it.
If you want a real cursed problem for Gaussian splats though: global illumination. People have decomposed splat models into separate global and PBR colors, but I have no clue how you'd figure out where that global illumination came from, let alone recompute it for a new lighting situation.
Also, since it's slightly hidden in a comment underneath the abstract and easy to miss, here's the link to the paper's project page: https://stopaimme.github.io/GI-GS-site/
I wonder if it's possible to do some kind of blendshape style animation, where you blend between multiple recorded poses.