As someone who 3D prints a lot, the cost of this make me kick myself when it arrived. I already had a waterproof airtag case mounted inside my rails in a harder to remove spot (in case it were stolen and the thieves tried to find it) for a lower cost.
I do like this one, I do like how it screws into the rail and is an easy install overall, but with the material cost being maybe a few dollars max and comparing it to the two pack of mountable, waterproofed airtag cases I'd previously picked up I think it may not be worth it in its current design.
I'd suggest TFL adding some sort of rubberized seal on the edge that faces the rail to try and seal things up a bit to mitigate dust and water from finding its way in as part of a future iteration or lower the cost a bit.