Quoted:
Absolutely stock it.
Delicious, mixable, easy to store, long shelf life, and cheap when you compare the cost per gram of protein to other protein sources.
Drifting a bit here, but a quality whey mix, chicken breast (2.29/lb at costco) lowfat greek yogurt, and egg whites cost pretty close to the same for the amount of lean protein they contain. Whole eggs and beans are cheaper sources. Those choices obviously carry some other calories that we might not want now, but would be useful in a scarce food situation. Lack of appetite is rarely a problem for me. I find it more enjoyable to eat my protein than drink it. Having said that, I use protein powder frequently. I sometimes use it as a milk substitute in cereal. I'll also mix it and add it to coffee.
A decent food storage friendly breakfast by mixing a cup of rolled oats, 1c water, and 1-1.5 scoops of flavored protein powder together. Stir or shake until well mixed. Let sit in a cooler overnight and eat it cold in the morning. You could also add or substitute some powdered milk, dried or FD fruit, nuts, etc. .
I could also envision this stuff being useful while on the move, when rations or FD food is being consumed.
My daily protein goal is 200 g, but would feel comfortable cutting that in half if the need arises to conserve and sufficient caloric intake is possible.
Although the enzyme argument is intriguing, my most frequent use is to supplement a meal that looks a little light on protein, so I usually have something in my stomach to slow digestion.