This is probably the first one of the "mastery level 10" achievements you'll get. The knife is incredibly OP and often a one-hit kill on non-super enemies so you'll probably be using it all the time. Even if you like going loud, it's worth knocking out a couple enemies with a thrown knife to get the party started, especially since silent sniping is kind of crap in this game.
Note that there's a glitch where using a takedown on super soldiers with the axe doesn't register for that achievement, so use the knife instead once you get that perk.