When I weaned off the cigs, I was always running out of pipe tobacco, doing the whole one pouch one tin one baggie of 2 oz at a time. I made a pipe and baccy budget and stuck to it when it was feasible. I acquired a nice collection in the 4+ years, and a decent stash ( over a year's worth at current consumption ) of tinned baccy. Having extra baccy on hand surely helped when I had to navigate through some not so pleasant events and the PAD / TAD had to take a back seat to more pressing life necessities.
At the present time, I still try to maintain a decent stock on hand, "just in case", and make a few large ( 20 tins ) purchases throughout the year, as finances allow. Even though buying baccy is as simple as filling up the online cart on the SPC website, walking over to the CS area, paying for the stuff, and then walking over to the shipping department and grabbing the tins, I find it somewhat of a hassle to do one tin at a time.
As for the whole TEOTWAWKI scenarios with having to use pipe tobacco as currency......it's definitely NOT something I am even remotely looking forward to. I remember food shortages and general unrest as a teenager in late 80s - early 90s in Eastern Europe. It was not good fun.