BBN
Fractal Fanatic
That is a great example of when it would make sense.I've done it in the past, especially on gigs/festival dates with quick changeovers. The reason being is if the FOH engineer is using a microphone mounted on a small stand, unplugging that cable and plugging into your AxeFX will change the signal from mic level to line level which could be a very big surprise for the FOH engineer.
Been to a few festival gigs with a shared backline cab and using the existing mic on that cab is much easier for an engineer.