seriously it's actually really fucking good emergency food (pre-soaked ones, in cartons or maybe cans, that is): Lasts a long time, has most of the nutrients you need (importantly both protein and fibre), and regardless of what anyone says the bean water is perfectly drinkable.
I prefer cartons because they're lightweight, easy to open, compact, and hey it's paper so in a pinch you can use it as fuel.

The fact that they don't strictly need cooking and come in water is really really really good, because you don't want to sit there crunching on dry beans, and if you don't have access to water it's completely pointless to eat anything.