I've been trying to think of use cases for this library.

I agree with non-blocking and running heavy lifting tasks in the backend, rather than on the fly in the template etc.

Unless the heavy lifting was directly connected to the action, ie, after save_post you need to do some stuff.. but for example of polling an API for something on the front end, this isn't the nicest way to do it. IE save_post could be sporadic, and you'd obviously not want to do admin_init, etc.. as it'd be way too much.

To date we just setup external crons that do heavy lifting and pre-populate transients, etc, so it's super fast for the template to grab the data it needs.