There are - the Elixir and Phoenix guides and docs are renowned for being some of the best in the industry.
The only reason there isn’t more on Contexts is because it is part of an RC and possibly because the core team are still ironing out details. In the meantime we have lots of community efforts to help fill in the gap - whether that’s blog posts, confs talks, forum resources or even answers to questions on the forum (and elsewhere).
It’s not about expecting anything - it’s just that I am personally a proponent of using professional material to learn because I feel it is the best way to learn 
your preference or milage may vary - that’s cool. As said, the Elixir and Phoenix guides are some of the best around 
(If you think the guides or docs are lacking in anyway feel free to start a thread about it.)
