Learning to read comes at a cost. Learning how to read may have some disadvantages for learning grammar. Children who cannot read yet often treat multiword phrases as wholes ('how-are-you'). After learning to read, children notice individual words more, as these are separated by spaces in written language ('how are you'). Source 1i.
I'm a big believer in reading because once you can read and love it too then a lot of things open up for you like learning a subject or developing your imagination. I don't believe in pressuring anyone to read because it can have the opposite effect.