[hrktb]

For a lot of instruments beginner lessons are not just giving instructions.

You might need to adjust posture for instance, and while you could spend 5 minutes explain it verbally in sequences of “move your left arm 5 degree up, no, up! slightly more to the left, your right arm moved down, bring it back[...]”; it’s just a poor experience and waste of time compared to in person moving their body to the right position (especially for kids).

Same if you want to check muscle tension or force them to only use some part of their body.