Proving your English skills is important, yet, unfortunately, there are some people who still do not know this fact. You might also be the one who still does not know why you should prove your English skills. So, to help you understand, it will be discussed in the following.
English level certification is required as a registration requirement in many university and visa programs. For example, if you are married to someone from the United Kingdom that you need to settle in the country, then you need to take an english test for citizenship.
In the job market, although rarely used as an official requirement, listing the English level certification will make you appear more prominent than others. In a broader sense, accurately measuring your level of English and being able to monitor change in levels over time is important for any English learner. Otherwise, how will you know if your English proficiency gets better? So, it is, indeed, better to prove your own English skills.