I'm about to buy a fender acoustasonic jazzmaster. It works great with some amps but in my opinion even better direct through the PA.
Still I wish to use the fx from the kemper, and be able to switch on my regular jazzmaster quickly if I break a string for example. I've got several sounds per song so I cannot simply create a rig with and without the amp section.
In that way, if I could assign the "amp" button on a fx slot that could be perfect.