The naming says it all, a loop in the ground wire. It happens when a direct wire makes a ground connection but also another wire makes a ground connection. Then you will create a so called closed loop which can build up a resonance frequency that can disturb the working of the electronics.

It hapens more over longer wires like in car audio where power cables and signal cables to the amplifier in the rear will end up in creating a ground loop and create a whining noise over the sound.

I do not think you have to worry about that with such short wires.