yes! I didn't even get to look at the rest of the reactive story in Spring Framework 5. This is, specifically, the functional reactive endpoints. Glad you enjoyed it!
Nice demo, but I don't get a point why we really need it? Comparing to classic Spring Web application, reactive version behaves much worse under regular load generated using Apache Bench.
2 things that come from the top of my head. I'm sure there are more. 1 it is asynchronous by design so you the client does not have to wait for the result. 2 you can have back pressure which means that you can tell the server that I want to load results 5 at a time. this way you implement the infinite scrolling that you see in facebook feed, youtube comments, twitter feed etc