I've been making these for a couple weeks now. The clear plastic part is generally sourced using the thick binder/presentation covers that come in 8.75x11.25 inch sheets, precut. The only requirement is a hole punch. Headbands can be any elastic material (I've been using button hole elastic for easy adjustment).
I'm not actually sure what you're saying, then. Why is the 3d printed version odd if the transparent part is easily sourced without needing a die cutter?
The part that is being 3d printed in these designs is easily sourced without a 3d printer. Look at Apple's design. It uses a piece of the same transparent plastic in place of the 3d printed part.
