If you need to connect a balanced audio signal (mostly from professional audio equipment) to a unbalanced signal (consumer equipment/ speakers).

I will use is to connect my self made active rear speakers to my pro- amplifier.

on anoter case I will use it to connect my master output from a semi-pro mixing console to an consumer amplifier, a few feet away and together with a lot of other cabling, so I want to stay balanced as much as possible.