One of my favorite units in game I would like to start out by saying. This is the recruitable unit of course. However I was wondering why they are considered Kataphracts since their horses only wear frontal armor as opposed to the Parthian/Greek versions.

Also, it seems somewhat odd considering that the Kataphract HA's on their roster are actually more heavily armored even though they are meant to be skirmishers first while the Royal Kataphracts are meant as lancers.