Flatten the curve 2x, you save twice as many people. Maybe 98% die instead of 99%, that's still twice as many survivors. But the cutoff point isn't static, either. The more you delay, the more capacity can be built up. So maybe flattening the curve 2x means saving 4x the people.
Bringing cases down from dozens a day or bringing them down from thousands a day makes a big difference in cost and lives saved. To stay at dozens or hundreds a day, you need to lock down early.