It's pretty much a no-brainer. Do masks reduce emissions of airborne infectants? Yup. Can you tell, at any point in time, if you are asymptomatic but contagious

It's pretty much a no-brainer. Do masks reduce emissions of airborne infectants? Yup. Can you tell, at any point in time, if you are asymptomatic but contagious and emitting infectants? Not without testing frequently, which I'll venture you don't. Can you tell who around you is immuno-depressed and might suffer debilitating consequences from being infected? Nope. And finally, is wearing a mask when you're out in public onerous? Nope! So there you have it. At very little cost to yourself, you can help protect strangers around you. I promise you those strangers to whom it makes a difference will notice, and you will have their gratitude. Mind you, if you are only asking from the angle of your own personal well-being, and making a difference to strangers at very little cost to yourself is not something that you can find much interest for, then it's a different question entirely.