The most important real use case of devices like this is as accessibility tech. Blind people everywhere are talking about devices like this.

It's the same with phones. I know blind people who have been harassed for holding their phones up to things as though they are taking pictures, but in fact they're using the camera on their phone to render signage legible to them, or having their phone (or a person on the other end) read it.

Banning this in a way that doesn't in practice cause problems for visually impaired people would be difficult. It might also be difficult to do in a way that doesn't harm, for instance, accountability for cops who are acting in public.

The impulse to "ban" is sometimes a bit naive imo.