My college piano teacher, Leonora Suppan, was a strong proponent of classical music. She was, after all, a professional, playing solo, with a string quartet, and a performer with a small but excellent symphony. She played classical, and she taught it.
There's good reason for this, because classical music includes most of the best that's ever been written. However, it's also important to know how to play popular music: tunes on the radio, worship songs, Christmas songs, oldies rockers, and more, for two reasons.
First, pianists are often asked to play popular songs at school, family gatherings, and church. Second, it's good for them to expand their repertoire.
Learning different kinds of genres teaches different ways of thinking, different skills, and different styles. That's why LHS teaches both classical and popular music.