One thing this piece leaves out is that if the operation/creation is in fact expensive, you want to make sure you have some kind of two-phase option so you don't inadvertently create multiple copies.

If the client crashes after the POST to create 'death star' succeeds and hence construction starts, but before it can read the response of the POST in the example and so never gets the pointer to the /queue/12345 from the response, if the client reissues the POST in the server should reject a second attempt to create a star named 'death star' just and give back the same pointer to /queue/12345. Or, if you want to be able to have two stars named 'death star', you should first POST to some endpoint to get a unique identifier from the server first, and then use that to kick off the creation of your death star so the client can reason about the current state.