It takes so long to go through your inventory and sell all the junk you get in one play session that it's incredibly easy to become lax about checking the confirmation window for each item. Really, when you have 40 items to dump, requiring multiple clicks and UI lag for each one is awfully time consuming. Not only would a buy back feature give us peace of mind, it would also remove the need for us to confirm every single time we try to sell something. This should definitely go into any UI overhauls they have planned for the future.