Interestingly enough, I've had a few essential oils folks express interest. Now, I'm all about essential oils...my wife and I both use them for some things. But my thinking is, if SHTF, are you really going to be looking up your local doTerra Rep? I've accepted them as vendors, and of course the answer is always "stock up on them ahead of time!", but my biggest interest lies in learning how to extract those oils on your own, DIY style. That would make more sense to me as far as educational opps and the Expo.
I’m distilled my own essential oil a couple of times. Trust me, it’s easier to just use the whole herb! In a survival situation, you are not going to want to mess with that process.
There might be a few exceptions, maybe stock up on oils for things you can’t grow, or for things where the oil has a dramatically different effect than the herb itself (rare).