I have a ZM 1. It comes in handy when you don't know where everything is. We do a lot of older schools and most of the cables are home runs. Over the years people add speakers and don't take into account the wattage rating of the amp. For us it's great to know the issue is 200 watts on a 150 watt amp or by testing individual speakers someone slammed in an 8 ohm speaker. For us it limits the amount of hunt and peck we do.
I hope this helps.

John 807