Of course there's value in what they're doing — to advertisers. As a user, I am not 100% comfortable with any tracking service, supercookie-based or otherwise.
KISSmetrics specializes in funnel analytics, not helping advertisers. I'm surprised by the number of people making that assumption.
I have a SaaS app and I use KISSmetrics to learn what sorts of things engage visitors and customers the most. It's helped me make critical decisions that benefit both me and my customers (by improving multi-step processes).
[Edit: Made the wording clearer]