Geometric analysis for Gaussian splatting is a bit like comparing apples and oranges. Gaussian splats are not really discrete geometry, and their power lies in overlapping semi-transparent blobs. In other words, their benefit is as a radiance field and not as a surface representation.

However, assuming good camera alignment and real world scale enforced at the capture and alignment steps, the splats should match real world units quite closely (mm to cm accuracy). See: https://www.xgrids.com/intl?page=geomatics.