Apart from acoustic considerations, the barefoot look adds some visual interest as well.

I agree that the production is top-notch. These kids are wonderfully talented. The girl singer, in particular, could well have a bright future in showbiz.

Dick Eagleson: I spent 20 years in the movie business. I am certain they wished to reduce unwanted noise. The production value of this piece is quite excellent, which reinforces my conclusion.

Likely so. Decades ago, during my college days, I had a set of headphones as part of my stereo setup so I could listen without disturbing my roommate. When playing recorded-live Broadway show albums the shoes of the dancers hitting the stage were always audible during numbers where there was both singing and dancing. This was much less noticeable when played through speakers into the room.

Chris: I think the kids all removed their shoes to avoid making unwanted sounds during recording.