Why do i need to hear my teammates footsteps?

I have to start by owning to the fact that I'm so seldom anywhere near my teammates that you could easily question my qualifications on this one...

But I almost never get confused between friendly movement and enemy movement in this game. When I'm close to my team the sound of their movement is consistent. When enemies enter the picture... well, they're ENTERING the picture and the sounds they make start as if from a distance and slowly increase in volume as they close the gap. Throw in one quick glance at the mini map and it's usually pretty easy to tell what it is you're hearing.

But I know what you're saying. And I'll raise you: why does a Mirage hologram get to make noise? I call that B.S.