There are a lot of purposes to read, it may depends on the goal of the reader. But on top of that purposes, we are just seeking for information and knowledge that we need. Reading is a lifetime habit of every individual. Even if you got a simple text message and you read it, you want to know what the message is and that's still a purpose. Also, I believe reading is very essential to everyone even the individuals who are visually impaired.. they have their braille system to help them to read what is being written in the book and that's because they have a purpose.