They are different enough for me to own both and enjoy good tones from both that are not identical. That and with Helix, the 4 aux ports make it a center-piece in most studios for running 4 cable method amps or Strymon pedals. And with the "Control" window in HX-Edit, I can set up all 3 Strymon pedals (via MIDI) for individually different patches per "Snap-Shot" all within "one" patch in Helix, and you can have multiple Snap-Shots per patch!
I keep my Kemper around cause it just sounds so damn good. . I purchased and downloaded some "Magnatone" profiles from "the Amp-Factory" @ 1/2 price Black Friday sale today. To me, Finding and Buying 3rd party amps (like the Magnatone amp profiles I found this morning) you can "not" do as well on Helix as you can on the KPA, because they are not so readily available.
I hope that answered your questions.