They say in the article that you linked that it looks like 20% of cases are severe and that the mortality rate is around 3% (though that is probably high because we are still early on in the epidemic). Last flu season around 1.4% of symptomatic cases ended up in the hospital and less than .1% of symptomatic cases ended with death. https://www.cdc.gov/flu/about/burden/past-seasons.html

As for the 5% permanent lung damage figure, ARDS is found in around 20% of cases with mechanical ventilation for around 12.3% (https://www.uptodate.com/contents/coronavirus-disease-2019-c...)

Survivors of ARDS often have decreased quality of life including lung damage and cognitive issues. I wasn't able to find percentages of these issues in covid-19-related ARDS survivors though.