Greetings!
Yesterday my buddy and me enjoyed my Kemper for quite some time. We changed between and compared cab vs headphones, and in that occasion we did try some pure studio profiles through the cab (with cab sim off of course). That is something I never would have done in a live, gig or even personal practice environment because I have always been told that a merged or DI profile is required for the best and most accurate sound.
To our big surprise, one of the best high gain tones I've ever heard from that little box came from a studio profile with a "theoretically" separated cab and mic! I was truly mindblown, as was he. I have done some tiny bit of experimenting with it before, comparing merged and studio profiles I have made myself (the studio profiles are a little on the dark side), and they sounded muffled and lifeless.
So, even though the cab-guessing feature in fact is extraordinary, it does seem to be reflected by the micing in some way, so it will never be a 100% true representation, but damn close enough I'd say! Especially if the micing is good, I'd have no issues playing a studio profile through my cab at a gig or practice.
Just though I'd share my experiences, in case some of you Powerhead or Powerrack users are shy of using your beloved studio profiles with your cab, or if you're thinking that you cannot use anything else than DI or merged profiles with your Kemper!
Have a nice day! 
