An interesting concept. Perhaps Kemper V2 needs to have impedance that matches the amps it is profiling.
Of course, I think where most solutions fail is when your amp and cab get into territory that is impossible to be modelled. Yes, it's possible, for example, you might have so much distortion or clipping that the Kemper will tell you, "No can do".
Can hear the hum on this video. Definitely not got a noise gate like the KPA. But is sounds pretty good imo.