While I agree that your product makes particular aspects of that process easy, depending on your goals, much of this effect is pretty easy to do in live. Whether it's messy or not depends on your particular aversions. If you want to use your own audio, and the effect of chopping it up into pieces isn't that important, then I would argue that dropping clips in live and setting a track to play a random clip is less work then dropping your own samples into Kontakt, which as you say, is a bit of a pain. The ability to then drop and control effects onto the track is far more flexible and interesting than using Kontakt. There is an advantage here as well that you're are learning more about your DAW which has value across all of your projects.
Again, I think it depends on the effect that you want and your sensitivity to how "infinite" it sounds. I can see a use case for both approaches. I use this kind of thing fairly often in my own "music" and, for me, instruments often get in the way. I've bought more than a few Kontakt style instruments that I don't use.
That said, if I just want the effect in the background and you want to set it up quickly, and, you like the samples that come with the instrument, then I would definitely choose the instrument approach.