From a human user perspective, HATEOAS is effectively just the web. You follow links to get where you want, and forms let you send data where you want, all traversed from some root entrypoint.

From a machine client perspective, it's a different story. JSON-LD is more-or-less HATEOAS, and it works fine for ActivityPub. It's good when you want to talk to an endpoint that you know what data you want to get from it, but don't necessarily need to know the exact shape or URLs.

When you control both the server and client, HATEOAS extra pain for little to no benefit, especially when it's implemented poorly (ie. when the client still needs to know the exact shape of every endpoint anyway, and HATEOAS really just makes URLs opaque), and it interacts very badly when you need to parse the URL anyway, to pull parts from it or add query parameters.