So what does it all add up to?
ER develops learner autonomy.
There is no cheaper or more effective way to develop learner autonomy. Reading is, by its very nature, a private, individual activity. It can be done anywhere, at any time of day. Readers can start and stop at will, and read at the speed they are comfortable with. They can visualise and interpret what they read in their own way. They can ask themselves questions (explicit or implicit), notice things about the language, or simply let the story carry them along.
ER offers Comprehensible Input.
Reading is the most readily available form of comprehensible input, especially in places where there is hardly any contact with the target language. If carefully chosen to suit learners’ level, it offers them repeated encounters with language items they have already met. This helps them to consolidate what they already know and to extend it. There is no way any learner will meet new language enough times to learn it in the limited number of hours in class. The only reliable way to learn a language is through massive and repeated exposure to it in context: precisely what ER provides