Представьте, что ваш младший брат либо сестра не желает учить британский.

Learning English is really useful! There is a lot of movies and books in English, and you would be able to read and watch all of them if you are able to understand English. Most video games are in English as well. You would be able to watch your favourite series and play video games before they are translated. Some of them would never be translated. If you speak English, you would be able to find people that understand you all around the world. You would never depend on Russian-speaking people abroad to help you. It would make travelling much easier and much safer!