https://www.sportschau.de/weitere/allgemein/corona-lungen-sc... (I did not found an english link)
https://www.lung.org/lung-health-diseases/lung-disease-looku...
Other fibrosis can be chirgurgically removed (happened to a semi-pro i know of), but this is not possible for the lungs.
So yeah a virus can do more harm than you can see from the outside. It is not just a cough. You don't know what else is going on.
The point of flattening the curve is to keep the healthcare system from being overwhelmed, in order to avoid a catastrophic death rate.
With a vaccine still 18-24 months away, we're all going to get infected sooner or later no matter what we do.
If we can keep this thing suppressed for another month summer might provide us with a bit of breathing room to figure out what works and stockpile supplies. But even if not I'd rather get this thing with the medical state of the art a month from now.