While I will agree that dependence upon wild foods could become crucial in a very unlikely scenario, I really don't put a lot of faith in that strategy. However, there is a much more significant benefit. Learning about your local food sources will inevitably acquaint you with your local area on a very intimate scale.

In the country where I have spent most of my time, the most important thing you learn in this process is the location and seasonality of water - where a pothole in an arroyo will retain water in the dry season, which springs are reliable, etc. Water is crucial for your own immediate survival, and it also attracts critters and in most ecosystems will support a unique flora, including edible goodies. Nothing beat local, intimate knowledge.

You are going to scope out the good camping spots, the usable rock shelters, good lookout points, the easy travel routes, and all kinds of useful things if you indeed are living off the land.

Even when I know all this, I am still keeping my canned peas handy...