If true and most people inside in China wear masks, what does it say about mask effectiveness?
Covid causes brain damage that lowers your IQ by about 7 points [1]. That's probably why China was going to great lengths to prevent it from spreading domestically. I still haven't gotten it, probably because I wear a vented N95 in most crowded places; I've long since given up on wearing a mask to protect other people who won't bother to wear one, but a fitted ventilator does lower your risk of getting the virus if you care to avoid it.
[1] https://www.thelancet.com/journals/eclinm/article/PIIS2589-5...
"In this respect, the battery of tests should not be considered an IQ test in the classic sense, but instead, is intended to differentiate aspects of cognitive ability on a finer grain. The tests had been optimized for application with older adults and people with mild cognitive and motor impairments."
Individually you may protect yourself with the mask (if you think it is worth it) but that's not how the policy makers should look at things on society's level. If most people will not/won't be able to use masks properly, then its effects will be very low.