<p>If all your extracurriculars are about something like music or art, would it be bad to also submit an essay talking about music/art? Is it better tell them something that they didn't know, or to explain the passion more in depth?</p>
<p>I would say to choose whatever displays your passion best. Art and music are great to talk about if you’re passionate about them! Choose one in-depth topic and expand on it so they can get to know you 
Good luck!</p>