> I have never seen how does HATEOAS deliver benefit over a wiki with good documentation - that seems like better effort.

Have you used a web browser? Do you see how it handles known content types from a new website that you haven't previously visited seamlessly without you reading docs and telling it what to do with it?

That is exactly HATEOAS.

In general, understanding REST is often easiest if you think about what browsers do, since REST is the key principal underlying the design of HTTP/1.1 and was largely a rationalization of the evolved behavior of the web per-HTTP/1.1.