If I understand the feature correctly - the Kemper does not know what part of the sound comes from the cab, and whats colored by the amp. It can guess though, how the amp would sound without the cabinet, and how the cabinet colors the sound, and separate the two..
Someone once wrote on this forum, that he found all the clean amps sound the same, if you disable other features from the different rigs, and that he found this very disturbing. The response was, that as the Kemper has to guess every time you split a profiled rig, the further you edit a profile the more "incorrect" the sound will be - according to the reference setup..