Why learning English? Sim, sempre a mesma pergunta.
Já alguma vez reflectiste sozinho nesta questão?
Quando o fizeres chegarás a uma só conclusão:- Because YES.

Learning to speak English well may be the best thing you can do to improve your life.

That's right. Do you think it would be fun to have access to information ? Talk and write letters to interesting people? Impress people around you whenever you opened your mouth? Make big jumps in your career, leaving others miles behind?