They are examples of "cinematic conversations"...which is the way the game advances the story in between dynamic events / quests... so they are sort of designed to take the place of quest text.
They were just easy examples, I think, to show off the animation and lip synching. I've very rarely (if ever) seen better facial animations or lip synching in MMOs...maybe it's just me, but I thought it looked pretty damn good in terms of the fluid way the animations went together, and how they matched up. Maybe if I played more single-player games, it would seem more common-place.
There are also full cinematic cut scenes, and dialogue that takes place in the open world...the cinematic conversations they used as examples aren't the only animations.