I know it's only a method of purchasing items from other users, but I think the idea of searching for an item you want and having to shop around in different areas, gives it that opportunity to travel and see what's out there kinda feeling.

Like I said I know it's only about purchasing items but it gives the crafter and traders there own involved world rather than simply putting an item up then someone buys.

It's not for everyone but I like a game that isn't just about bossin mobs and levelling up.
I've seen too many of those boring MMO's.

Having said that it's a good time to mention the fieldcraft work which is in depth where you have to actually work for your results rather than clicking a rock and then he mines it.