Now let's consider what would happen if you had never studied before. You would probably be able to speak the language somehow, but if you don't know arithmetic, you would have a hard time shopping. However, if you don't know anything about arithmetic, you will have trouble with shopping. Also, if you have not studied social studies, you would not know what is sold where. If you can't read, you can't look up what you want to know in books.
If you don't study anything, you will be very embarrassed in your daily life like this. If you are an elementary school student, you will be living in society for decades to come. And when you become an adult, you will have to work. For that time, it is necessary to study little by little from now on. You do not study to get a good score on a test. You study because it is necessary for your own future life.