Curious. Since you both worked at Heap before, is there a potential conflict of interest or Non-compete that you may have/had to worry about ? I don't know the details of Heap or Segment but I am assuming this service is similar to them if not closer ?
Segment (and presumably this solution) is more like an event mux/demux. All your disparate event sources connect in, and you send the data to places like Heap to visualize it. Segment's value is acting as a central, common location for your event data.
Heap's primary value is visualization/analysis for things like retention/etc. You can collect data directly through Heap as well but I wouldn't say that's the primary value of it.