These things are fascinating!
The one sold by
Wilkinson's seems a less common variety to the extent that the holes on each
face appear to all be the same size. On most of these the holes are of significantly different sizes.
The one that appears to have solid faces is actually an icosahedron (20 faces) as opposed to the usual dodecahedron (12 faces). Most of the faces on an icosahedron arn't parallel to opposite faces, but interestingly on this one the two faces that ARE parallel to each other DO have holes in them. Another interesting aspect of this unusual one is that the ball "feet" are all of different sizes.
One dodecahedron has been found where most of the holes are circular, but one pair of opposing openings are elliptical instead.
The size of these things varies quite considerably from about 4cm high to 11cm high (about fist-sized), so if they were a
type of measuring device it would seem to have been for a case where standardization wasn't needed.
Another aspect to these is that they have pretty much all been found in
Britain or
Gaul, so if they were utilitarian it'd seem it was for a use limited to that region.
What
comes to mind with the ball feet (which seem an important component - always present, yet adding to the difficulty of manufacture) is that they would have allowed these to stand steady on most reasonably (but not perfectly) flat surfaces.
I've read one theory that they could have been used to
help carve round slingshot projectiles of various sizes, although they do seem a
bit elaborate for that. The lack of size standardization, and existence of ones with all equal-size holes would seem to mostly rule out any use as a distance measuring device.
Here's a more typical one showing the different sized holes.
