> "It turns out that leakage dominates over filtration."
That sentence does not translate to "cloth masks are useless". In comparison, a bullet-proof vest may only protect part of your body from danger but it's still better than nothing if you're being shot at.
What you've basically said is that if a mask is not 100% effective it's useless. My analogy stands, just because a bullet-proof vest is not 100% effective in stopping all bullets from hitting your body, it doesn't make it useless. Some protection is better than none.
That sentence does not translate to "cloth masks are useless". In comparison, a bullet-proof vest may only protect part of your body from danger but it's still better than nothing if you're being shot at.