The idea is that you have say 1000 ICU spots available. Based on your numbers 4.5% of the cases are deadly, but let’s say 10% are severe-to-deadly and require two weeks of ICU care. So that’s 6,700 people or roughly 94,000 man-days of ICU time. In other words if you slow down the rate of infection enough you could fit that 94k into the 1k of beds over time. But if all of them get sick on day one, you are fucked.

Social distancing is about slowing down the spread, not eradicating the disease. What will eradicate it one way or the other is the immune system or death: once you’ve had it you are unlikely to get reinfected or you will die. To avoid the latter case you need ICU time or eventually a vaccine. Also consider that buying a month of time means an extra month to provide more ICU beds, better testing capacity, better understanding of what is effective prevention, etc.