Sometimes it's only convenience. In my office I hooked up 3 PCs to an Aune X1. I can switch them as I need and control the volume for speakers and headphones...
I just tested it with the AKG and again the Shure. In the range of tolerable volume (30/99, low gain) not the slightest noise.
With high gain past 50/99 a slight noise perceptible - but there you should pray that you do not accidentally press play... :eek:
I guess my first test of the Shure was...
I only tested it with my Shure SE535 and it has the slightest amount of hiss. I'm not sure (no pun intended) of their sensitivity.
Could do further tests with AKG K3003, Aurvana InEar2, Zero Audio Carbon Tenore and some more if needed. Don't know if that helps out, though.