Why POM you might ask?
Although they do not have a gloss finish, they feel silky smooth due to the material. They also give a different typing experience due to density of the material.
POM has a density of 1.41 g/cm3 and ABS and PBT has 1.1 and 1.3 g/cm3 respectively. This causes a different sound profile, allowing them to sound a bit like marbles with a "thocc".
They have excellent mechanical and chemical resistance properties!
Here is a picture of three common plastics used in keycaps after being soaked in nail polish remover! You can see which one is the clear winner!
We did a torture test on them and the full results could be seen here: