I know when the older Hitman games it was a very important tool. But honestly in my playthroughs I never bother equipping it unless it is for to complete a challenge.
I find to knock people out the non-lethal melee weapons are a lot faster and then you can just snap their neck and kill them afterwards if you want to anyways. Really the only upside is you can instantly drag people after you strangle them but I usually am never in a position to where that would give me the split-second advantage it offers anyways.
And all non-lethal melee weapons are completely silent when you attacked from behind if I’m not mistaken but I could be wrong. Do any of you think that it is a vital tool that you must have?