That's a good question.
I have the unpowered Kab.
I've only done 2 outside gigs with it in a parking lot last year (covid sucks). I used a Seymour Duncan SD700 amp with it. It was absolutely more than enough not only for backline but for my only sound source (no input to PA).
Now, with the latest Kemper update we have the Power Amp Boost. With that and my Camplifier 290 (2x90w) I feel I can get enough power to reproduce those gig volumes.
That said, to me it is only going to be for small gigs. Otherwise it is perfect for personal stage monitoring along with your Main out to PA.
In short, although I don't own a powered Kab, I'm betting the experience will be the same as mine.