As hikermor suggests, in a true TEOTWAWKI scenario, just using an ordinary crow bar to break into a locked space is quicker and less hassle than lock picks. My 12 gauge pump gun with slugs would probably also do the job nicely. Brute force methods also have the advantage that they work on keypad locks or various other high security locks which don't lend themselves to picking.
Lockpicks are lighter, smaller, and make less noise. With that said if I could only carry a crowbar or a set of picks, I would choose the crowbar. Ditto shotgun although for other reasons.
In non-TEOTWAWKI situation, just find the person with the key to let you in. If they don't want to let you in, you probably don't belong there anyway.
In one case, my key to a padlock was lost (for good) and it was much quicker and easier to pick the lock than to cut it. In another, friends bought some property upon which was a trailer where the key was lost; I was able to quickly and non-destructively open it for them. In neither case was there the least bit of ambiguity as to the propriety or legality of my actions. These are certainly edge cases, and at least for the trailer a locksmith could have been paid to open it.
My interest in lockpicking is as a hobbyist; I am not a professional nor a survivalist. I seriously doubt I would ever be in a TEOTWAWKI situation, much less one where lockpicks would be useful. I also agree that in almost all cases if you don't have the key or the person with the key, you shouldn't pick the lock.
Would I spend the time and effort to learn how to pick locks for prepping purposes? No. Since I spent the time and effort to learn how for other reasons, do I have them? Yes.