It depends.
Kemper was originally designed to capture and reproduce a mic'ed tube amp with a cab. The idea being that this is what the audience hears through the PA.
The hole in this logic was that this sound isn't what the guitar player was hearing on stage (amp in the room). As a result, Kemper (and others) made solutions that would provide the guitar player with the "amp in the room" sound on-stage while delivering a different FOH result (that sounded good through the PA).
IMO the real issue is that the "amp in the room" sound is ONLY important for the guitar player. The mic'ed amp sound is what is spread to the audience through the PA.
So ..... if you play in a band that relies on the sound from the amps on stage to fill the venue, than something like the Kemper Kabinet that duplicates the "amp in the room" sound is pretty important.
If you mic your cab and the PA provides the sound for the FOH (most more successful bands do this) then the local "amp in the room" sound is just for the guitar player.
If you just play for your own enjoyment, again, the Kabinet route is a very good one.
Over the years, I have grown to love the sound of the mic'ed tube amp sound and the "amp-in-the-room" is now piercing and unpleasant in comparison.
Note: Bands that rely on "Amp-in-the-room" stage volume also have an issue with balance of sound in the venue since these cabs are very directional and blast one side of the stage while the other side the guitar volume is very weak in the audience. The answer to the problem is NOT to add more cabs by the way