It's a jungle out there so you need a weapon. Some brands of survival bracelets include a small knife tucked neatly inside that can be used to cut the paracord, dig the notches in your fireboard or snare trap as well as kill game and filet it to be cooked [sources: Cabela's, USParaband.com].
A good, sharp knife is also nice to have when you're the prey. Ward off attackers with your cutting piece. Then prepare them for chow time.