Knot tying is definitely an "art". I try to come up with handy ways to carry paracord because in a survival situation, or even if you just get turned around on a hunting trip and end up spending the night in the woods, cord is PRICELESS! You can do anything with it! Use it to tie up your rain parka for shelter, make a hammock, tie up meat away from predators, pull out individual strands and use it for fishing and snares (550 paracord has 7 internal strands), lashing for making a litter, or splint, or shelter, or raft... How long would you like me to go on?
Cordage is arguably the single most valuable tool you can have if SHTF. If your willing to get a blister or two, fire only requires a couple sticks.
Been putting together an order with my wife, and these are on my list of wants.
Knot Playing Cards - Learn to Tie Knots