This is a language problem that's developed over the past few years. Rooted hair is a specific term meaning punched-in hair, they use soft vinyl heads, which usually can't hold detail as well as harder PVC heads, that's why people call them "Barbie heads", because inevitably rooted hair heads don't have as much detail as sculpted hair heads, it's because of the plastic used. The hair used in rooting is typically nylon, it's still plastic hair, but it's strong enough to withstand the pressure of the rooting process, but it's not fine like real hair is in-scale.
However, as realism increased, customizers started gluing in yak hair, or other fine animal hair to create better results, and people just started calling everything "rooted hair". I assume that folks never really understood that "rooted hair" defined an actual process, but here we are in a situation where manufacturers are using the term "rooted hair" in a way that really undersells what they're actually doing. The gluing-in process is much more labor-intensive than rooting, so it behooves the manufacturers, and customizers, to come up with a more accurate term for their process.
In this case, InArt is gluing in the hair.