It’s just her way. She teaches the entire yoga practice with her voice and demonstration with her eyes closed.
You could lie on your back for the entire practice and she would never know.
Cutting off one of your senses can enable you to focus more on yourself and sensations in your body.
You can’t get the practice wrong as all you can do is follow as best as you know.
How would you approach life if you knew that you could never get it wrong?
Would you be more willing to step out of your comfort zone?
How would you feel if there was no judgement from yourself or anyone around you?
If life is happening for you, then every experience you have is in your favour. Even the ‘bad’ experiences. They are lessons or learning experiences which help you evolve.
Are you willing to venture life with your eyes closed to the criticism and judgement?