Lorenzo: In most MMOs, when you come across a town, you'll see all the NPCs standing in their designated spots; buildings never change, and there are only a set number of objects and characters to interact with. But for WildStar's Settlers, towns aren't so static. While all the other Paths can only interact with what they see, Settlers expand their environment by repairing buildings, revealing new merchants, buffs, and even quests.
Not every town you stumble upon will be fully functional. That's where the Settler comes in. If there isn't a Settler around to fix a busted transit system, guess what? Everyone else will be unable to use the temporary mounts for fast travel. If you see a run-down building in town, chances are a Settler could fix up the joint, so you'd be able to grab a pint and possibly a few buffs from the upgraded bar. Why go out and trudge in a dank cave while there's plenty to do in your own settlement?