Yeah, umm.. that traders are offering fetch quests (for example) that not only give you the loot as you are 'looting' but also give you bonus rewards once you return with the satchel. So what you say is not actually true.
Oh, and that triggering the quest actually resets the POI, so you can run it as you arrive (without triggering the quest marker) Then once you finish it, you then trigger the quest whilst the layout is fresh in your mind and completely clear it in a third of the time.
So yes, traders/quests are a little broken atm, its a nice idea, but they need to be implemented a little better. (ie: perhaps make it so that they don't refresh the POI, and if you have already cleared it prior (due to a random house looting), then it remains cleared, loot and zeds. The most important part about this though is that the trader should never offer the same POI twice, if a satchel has been retrieved, then no more quests for that location)
(and this is not even taking into consideration the mind numbingly easy 'buried stash' quests and their bloated rewards)