The dodecahedron Wikipedia article already mentions spool knitting [1]. This awesome video shows knitting for different-sized fingers on a 3d-printed replica [2]. An initial question could be whether 6 equally-sized holes align with each other, or if there are 12 different hole sizes for finer sizing options (hard to tell from internet images). And as for no wear on the tool, hardness of wool << metal. It's not as if the dodecahedron is being used as a pulley block.
2. Hair braiding
layer8 mentioned these dodecahedrons being found in wealthy women's graves; I'd offer they could have been for braiding hair -- seemed important to wealthy Roman women back then [3].
Speculative scenario:
Could sit in a chair with back to a table (or just lie down on the floor), with hair strands laid outward from the person's head. Selected strands are pulled through the dodecahedron tool, and braided. The dodecahedron tool moves incrementally away from the person's head as the braid forms. The knobs on the top-side help organize each strand, and the knobs on the reverse (bottom) side creates standoff for the braided hair to emerge. Hands-free tool for making perfect mini-braids.
I wonder if some statues might be realistic enough to depict braids [4] (and from similar time periods as dodecahedrons' manufacture date) to match with a 5- or 10-strand sinnet pattern (e.g., ABOK#3037) [5].
[1] https://en.m.wikipedia.org/wiki/Roman_dodecahedron#Purpose
[2] https://youtu.be/76AvV601yJ0&t=517 | from: https://www.mentalfloss.com/article/514246/are-roman-dodecah...
[3] https://unpodipepe.ca/2017/01/31/hairstyling-ancient-roma/
[4] https://en.wikipedia.org/wiki/Roman_hairstyles#/media/File:K...
[5] https://books.google.com/books/about/The_Ashley_Book_of_Knot...