There's probably more complexity than "they work" or "they don't work."
My 2c: government shouldn't be mandating anything, but should be making recommendations with explicit and lengthy reference to the reasons for their recommendations. Private organizations should make choices for their own property. Private citizens should make their own choices based on their own situation.
Work with elderly? maybe wear a mask and use a lot of sanitizer.
Work outside all day? maybe don't worry about it.