Short version, I can create a segment that says a visitor that has event1 and event 2, but you have no way of knowing how that visitor interacted with those two events- which event happened first..
For instance if I create a segment that says 'visitor that ordered and wrote a review', we don't know if he/she wrote a review and then ordered, or ordered and wrote a review.
This is just a simple example, but there are many other use cases for building segments based on sequencing.
