The Radial rack should help out a lot of people, and is very different from any line mixers out there as that isn't quite what it is anyway.
Usually they post a user manual at their site fairly early, showing suggestions for routings and use cases. It wouldn't surprise me if this unit has some practical applications in the studio as well as live.
Indeed though I'm uneducated enough to wonder how it's a lot better than the PreSonus gear. With them announcing the USB-C option now I can't see where the extra cost is in the KL-8 although the components may be better?