Not one professional public health authority anywhere globally has ever described masks as worthless.
Well, of course. But when you spoke of the worthless masking up of society, were you speaking only of people the wear a mask totally wrong, such as covering only their chin?
When they are not changed.
When they are not changed, they are still not worthless. Unless you mean “worth less”, as in less effective than they might have been. But I think you are referring only to health care workers who wear N95 masks to protect them selves. Regular consumer-grade masks are not nearly as effective in protecting the wearer, but they are very effective at protecting the rest of society from the wearer, even when not changed.
When they give the wearer a false sense of security.
That’s the fault of the wearer, not the fault of the mask. The mask is still very worthwhile, when properly understood.