Hello There!
Reading and writing is an essential skill to have in life. Personally I love reading books in my free time because it's relaxing for me. With reading, it improves your vocabulary. In books, you will get exposed to many new words and you can expand your vocabulary. Believe it or not, when you read you brain is getting a good work out. This is because the more you read, the faster your brain recognizes words and processes them faster.
Writing helps you also learn like reading but in a slightly different way. Instead of helping your vocabulary as much, it will help you with your grammar so people understand what you are talking about. It helps your brain again because when your writing, your plan is to use new words and brain storm about what to write.