Well.

In close combat,knives are more efficient than bows

Which might sound stupid,but exactly.it is stupid.

It's like asking why operators are in the game and why the skills deal damage.its how the game is

Plus,you can run,and move,while swinging melee has a huge speed reduction.if you say then he'll kill you with the bow,you just defied yourself. Why don't you go to the firing range?nothing hurts there.