Honestly, it matters. Current web technologies aren't the end game solution for interfaces and, IMO, are pretty horrible to work with for that purpose. (Pretty beaten up topic by now, but lets take a moment to think for a second about vertical centering in HTML+CSS. /sigh </rant>)

Still, my answer was just referring to the fact that this is not using web tech, and thus, not using servo or any other existing browser engine.