And yes, it is just a start -- the Insignia removes all movement-impairing effects, but it doesn't have any extra resilience like the epic PvP trinkets you can get from turning in honor, so if you're doing lots of PvP, you'll still want to grind for the other trinkets. It is equivalent to the trinket sold for ~2800 honor (that used to be a class-specific trinket, but is now basically faction-specific), just a little easier to get.
I also checked the Halaa PvP quest in Nagrand, but there's no extra trinket reward there, just the usual daily gold and the extra honor. The Armory shows that this is the only place you can get it, save for the usual honor vendors. So if you haven't nabbed a PvP trinket yet, go take some fortifications in Hellfire.