In my opinion, I agree that music, art and drama is as important as school subjects, specially at primary level.
First, children at primary school is very young. They not like only read and write all day. Music and art help they to be happy and creative. For example, when child draw picture or sing song, he feel good and not get bored in class. This things make school more fun.
Second, this subjects help develop important skills. Drama teach children to speak in front of other people and not be shy. Art improve imagination and music help with memory. Many doctors say that creative activities is good for brain development in young age.
However, some people think that maths and languages is more important because children need learn them for future job. But I disagree with this idea. If child only study hard subjects, he can become very tired and hate school.
In conclusion, I strongly believe that music, art and drama should be equal important as other subjects at primary school. They help children grow not only in knowledge but also in personality.