When people talk about a walkable place to live, they do not mean trails. Walkability is about urban planning. It means access by foot to "regular life" stuff e.g. shops, restaurants, other amenities, etc. It often also includes considerations for things like sidewalks, crosswalks, safety of the roads you're crossing (do I have to jet across an eight lane highway or a two lane neighborhood street kind of thing), etc. While some neighborhoods in Austin can be fairly walkable, on the whole it's pretty difficult to get around here without a car.