Oh, I know much of it like the back of my hand, and have spent plenty of time doing outdoorsy stuff, and have found myself in a few genuine survival situations, and I'm here to spout crap opinions on the web still, so...!
It's mostly handy for "was it the one with the serrated leaves, or the one with the smooth leaves which is toxic?".
If you're going to rely on stuff like that, its best to commit to knowledge and practice.