A potential cure. Buying time until a vaccine or remedy.
Flattening the curve can also potentially save lives because it buys us time until we find a cure, preventive vaccine, or effective remedy.
If a cure is found, then the AUC at the tail end of the flattened infection curve will be larger than that of a non-flattened curve. Those are effectively less people infected (on the infection curve), and lives saved (on the mortality curve).
[Insert graph 7]
The AUC after the cure represents the number of people who avoided the illness. That number is larger on a flattened curve. Ergo, flattening the curve can save more people from being infected if a cure is found.