Show HN: Leptus – Erlang REST framework that runs on top of Cowboy web server

I don't want to be a killjoy, but why do so many "REST frameworks" focus so much on the transport (HTTP) and not so much / or at all on tools to create and manage hypermedia representations (links, actions, domain objects)?

I'm curious what usage this saw 2014-2015, and what the current drive is to bring it back to life.