the missing piece. They are effective if you don't touch the exterior and if you dispose of them properly.
most people I've seen touch the infected exterior constantly. reusing the same mask donning it on and off is a joke.
You have to define "effective". They are effective at catching large moisture droplets.
In healthcare settings, that are regularly sanitized, and when workers actually observe proper mask protocols, there is a slight advantage in wearing n95 masks against bacterial infection. That's how masks are effective
Plain cloth masks are effective at increasing risk of bacterial infection, such as bacterial pneumonia throughout the 1918 flu pandemic, which was actually responsible for a large percentage of deaths.
They are ineffective at slowing the spread of viruses.