The reason why your English proficiency is so important to universities is that English is the official language of 53 countries and is used as a manually known language by people from all over the world.
The English language is becoming more and more common in the world. It has become part and parcel of almost every existing field. We use it as an international language to communicate in many fields. The English language opens ocean opportunities to those who speak this language anywhere in the world.
International English language testing system is recognized all over the world and needed by universities. IELTS is accepted as proof of English language proficiency by over 9000 organizations in addition to 135 countries for education immigration and skilled functions. This is the most widely known English test across the world.
By taking the IELTS test, you will already be applying your English knowledge as if you will already be applying your English knowledge as if you speak daily with English native speakers. The test is meant to assess completely different English language skills.
By demonstrating your English capabilities with IELTS, you prove to the university that you have the language skills necessary to succeed. They know that your ability to speak and understand English will greatly enhance your school experience as you collaborate with and live alongside students who grew up with English as their first language.