It can be life-saving, especially if you're out alone and something happens. On top of that, it's a basic survival skill which pretty much anyone should pick up at some point or another.

Picture the following: on the way to your blind one fine morning in search of a big buck, you happen to step wrong. You happen to severely twist your ankle while you go down, leaving you stranded and with only a single bottle of water. You're hunting in a secluded spot and even if you have the first aid skills to make a splint, you have less than a day's worth of water with you.

In more extreme situations, such as desert hunting, it becomes even more imperative. Finding water in these circumstances can be challenging enough, but you also need to know how to purify it even then or you risk making yourself quite ill.

The ability to purify water, even without specialized equipment, is another important thing to know. Even running water can be suspect, and making yourself violently sick while trying to survive isn't going to help you out at all.