You know...this makes sense. That those were added for Quests. However, if that's the case it could be done so much more interestingly.
For instance, perhaps the vast majority of the time in the POI you don't get the treasure vault version of the loot room.
IF, however, you're doing a quest, then the loot room is more "treasure vaulty".
This would incentivize questing, in addition to making things like Lucky Looter better overall (and less overpowered, in general).
I also think that it would make a lot more sense to find destroyed or deteriorated stuff as primary loot. After all, this is an apocalypse, finding pristine unopened M60s somewhere people lived makes little sense. (If I were the house owner and the FedEx guy dropped off my Shotgun Messiah create you'd damn well better believe I'm chopping that thing open right away. And if I'm the FedEx guy and I drop a Shotgun Messiah crate off and no one signs, you better damn well believe I'm coming back by in a week or two to see if anyone opened it... If not, that thing may just find its way back on my truck...)