Future archeologists: we believe these were to provide a form of transportation for their miniature gods, as the large humans honored the devices with novel patterns.

Reality:

Spinny boi

By the looks of it, the Romans were size queens and kings. The frescos and mosaics of Pompeii support that theory.

Grandma knows how to use it.

https://www.metmuseum.org/art/collection/search/100008377

I cast fear on Julius Caesar!

Uh oh, Julius Ceasar's only path is through most of the members of Senate. Each member gets one attack of opportunity.

Go ahead and roll 23 dodecahedrons for hits! Brutus also gets advantage for backstab.

I'm not sure if this is a hypothesis with any level of acceptance

Unless an actual record is found describing what they were used for, it's all just guesses anyway.

These devices are rather small and most amphora seem to be much larger. The shape of amphora helped with shipping, so they were typucally larger than a device that can fit in your hand.

those bottles with pointed bottoms the Romans had, don’t remember the name.

Amphora

Dang it, someone thought of it already

Maybe it is a knitting-pastaing-horsing multitool

There's no horse on it, silly!

how much pasta you need to knit a toga or some shit

I 3D printed her a model of one and it's sitting on the mantle over her fireplace.

That kinda hints to it not being very useful then...

Archaeologists in 2000 years will be puzzled again. "Plastic dodecahedra found near broken mantelpieces, what could it be used for? Anyway I made one out of technetium for my grandma"