The fundamental assumption here seems to be that users are basically interchangeable: > There is no real need to keep observing the same thing multiple times

The fundamental assumption here seems to be that users are basically interchangeable: > There is no real need to keep observing the same thing multiple times That may be true for some simpler products, but I helped out with some user research on an analytics tool, and there was quite a diversity of feedback from the first two batches of users.