NPC vendors are a good balance between being a trader and not having to stand around in your shop waiting for people to show up. Think of the NPC vendor as an employee of yours who's job it is to sell your goods while you work on more important things such as crafting and gathering.

Vendors did not come free in SWG. You had to reach a certain skill level as a crafter/trader to have one, and you had to pay a fee to keep them running (like paying an employee to work). Medium level traders had limits on their vendors too, as in how many vendors you could place, how many items the vendors could hold, etc. Higher level traders were able to place multiple NPC vendors in their shops, and even customize the look of them, place more items in them, etc.

Just food for thought. Everyone I know who ever played SWG loved this system for running their business.