Nowadays, English is described as "the language of opportunities", but there are a lot of people who do not think the same, also they think that learning English or any other language is a waste of time. There are several points to consider.
On the one hand, there are a lot of adventages for example you can meet new people and make friends from other countries, you will be able to undertand the lyrics of American and British songs, it makes easier to get a job and if you, for example, travel to England you will undertand their culture better because you can speak English.
On the other hand, there are people who think that it's no necessary to learn a language because millions of people speak Spanish and there are many jobs that do no need foreign languages. One of the disadvantages is that it takes a lot of time and effort.
To sum up, there are advantages and disadvantages but, from my pint of view, learning English or any other language is very important for your future.