The value makes the mask safer for the wearer. Some masks don’t include because they are cheaper. Not a bug, a feature.
The problem is that if it doesn’t have the flapper, your breathing is even more obstructed, and the seal is harder to maintain, and the mask is likely to clog quickly.
The people who initially said masking was a bad idea for the general public were telling the truth then and they are lying now.
I agree with that. Ingraham had a pretty good rant on it the other day.
The ‘science’ on PPE and spray transmittal has been pretty much settled for a looooong time. That’s why Fauci and others back in March repeated what has been standard. Then it became a political and now it’s a full on wedge issue.