GS does 2 things that makes it great for _rendering_ and _world approximation_, it's a view-dependent "fuzzy" thing, so rendering-wise you don't need to fill in blanks of reconstruction, they also encodes view dependent things like reflections (that should help an AI model infer beyond-view details).
The issue of real voxels (not MC style) is that they fill in fixed spaces that then can creates gaps once you start animating, you probably have the same issues with GS (but that's probably why they are doing exports).
The issue of real voxels (not MC style) is that they fill in fixed spaces that then can creates gaps once you start animating, you probably have the same issues with GS (but that's probably why they are doing exports).