Check your stats. 0.77% of South Koreans who tested positive for the virus have died already, and more of them will die in the future. The CFR is likely to be above 1%.
When those same experts see numbers coming out of Italy, they believe very strongly that the number of infected is far higher than being reported because testing is not as widespread.
But it has a key context: that's the CFR for when all patients are treated. In most of China, there were never enough infections to trigger a healthcare system collapse: that's why in all but one province, the CFR was indeed ~0.4%.
In one province, Hubei, the medical system did collapse.
Its CFR jumped to 3-4%. That is worth going to extreme measures to prevent. In the USA, that would amount to ~10M dead.
That is not a seasonal flu.
I think a superior approach for most of the world is one along the lines of Singapore, Taiwan, and South Korea: extensive testing and contact tracing and limited but real quarantine measures. But, yes, everything should be on the table to prevent the nightmare healthcare system collapse scenario.
1) But # infections were growing exponentially, we need to use numbers from the same cohort, which implies much lower # infections & higher CFR. Naive CFR will go up once infections grow more slowly. (It already is higher than 0.6%).
2) South Korean confirmed cases are much younger than their median age, mainly between 20-29 years old (perhaps because of where superspreading events happen—that church). This age group has a much lower fatality rate from Covid-19.
3) # hospital beds per capita in South Korea is second highest among OECD countries (1st is Japan) and ~4 times that of the US. They already have patients waiting for beds. Most countries will do much worse if they reach the same # infections per capita.
I understand that this is NOT the flu, but it seems like the best data we have puts the most pessimistic CFR at about 0.6% if you look at the South Korean data (who have done, by far, the best job testing en masse).
I agree that slowing the spread of the virus to help our health care workers avoid being inundated with admissions to the ICU is worth while, but I'm extremely skeptical of embracing what China has done.