High-Z input in audio interface
The disadvantage of a high impedance input is susceptibility to noise.  That is, it will be better at picking up interference from other devices in the area.
Noise from other devices can get to your input through capacitance effects or inductive effects.  Those effects can't deliver much current, though the voltage may be very high.
The noise sources are, in other words, high impedance sources.
If your input is high impedance, then the voltage stays (fairly) high and will be carried through by your amplifier.
If your input is low impedance then it will &quot;short circuit&quot; the high impedance noise sources - the noise voltage will be much lower and won't be as noticeable compared to your real signal.
The down side to a low impedance input is that you have to drive it with a low impedance source.
You need better shielding on a high impedance connection than on a low impedance connection - but then you need a stronger source to make use of a low impedance connection.