If the cloth masks are worthless against viruses; I don't see any reason to use them to prevent transmission of viruses.
The "experts" who say it stops the spreading of this virus to others evidently don't understand how small this virus is. Breathing through a cloth mask is like breathing through your screen door to the virus.
What the cloth masks do is give some people the illusion they are doing something. They aren't but it gives them some feeling in control. It's a placebo. I can say for those who take comfort using them are probably spreading the virus faster which isn't such a bad thing because the spread is inevitable but mental well being is important too so in that one way the cloth masks do something positive.