I’ve rarely seen it used beyond very, very basic things in Angular projects (and I’ve always wished I saw more of it, actually). Maybe we just work on totally different kinds of projects.
I am the guy who doesn't use it, but people used to recommend using it for "event-driven architecture on the front end" - clicking a button is an event, typing text is an event, hovering over something is an event, and there could be multiple subscribers. The example use-cases people give are really contrived. The functional crowd also pushed it. Again, to me it's another trend like Web Components that never really took of in the mainstream. Yes, people use Web Components and RxJS' full power, but it's not something to learn when you are looking for practical, widely applicable skills.
If anyone still cares about this, here is a helpful site that you can understand without knowing anything about RxJS:
https://rxmarbles.com/
