[onethought]

Some people have actual breathing conditions (pollution sensitive, allergies etc) that require a proper sealed mask, without the valve the seal will often break.

Valves with a diffuser cap that stops the air jetting out are probably the best if you have this restriction.

[pessimizer]

If those people need a proper sealed mask now, they also needed a proper sealed mask before covid-19. In actuality they were not wearing a mask at all unless they were either Japanese or usually in a hospital/nursing home/hospice and on a short trip outside to see a specialist.

That being said, I have breathing problems and the combination of masks and cold weather is awful. I'd love to wear something that released the moisture. It wouldn't be nice to the people around me, though, and I can just get away from people to take a break if I need it.

[onethought]

Yes. I meant people who wore masks before Covid.