Earlier quoted context omitted.
This seems more like a gallery of art/starting point than a "use this as-is", so I'm sad to see this comment on the top of HN since as a show of what can be accomplished with checkboxes it's amazing. We front-end devs would benefit from a lot more works of art like this, and then people trying to implement them into real systems would need to make them accessible. Similar to how we benefit greatly from Dribbble. If w…
I agree with the sentiment but there are problems besides accessibility here: 1. Crosses and squares being used instead of check marks. 2. Circles being used as containers instead of boxes. 3. Toggle switches being presented as checkboxes. Maybe 5-10 of these are good inspiration for checkboxes.
Naming element types by their style or form (box) rather than features in an implementation that encourages separating style leads to a more general problem.