This matters a lot. The first number is obviously important. The second matters so Italy can plan for whether things have peaked yet, or how many weeks out until it does.
Or, if applied to the US, 10 million.
Alternatively, we can shut down the virus in the same manners that China, South Korea or Singapore have been doing, and keep it supressed until we develop efficient treatment.
Unfortunately, that means shutting down all affected regions really hard, and maintain a high level of supression for maybe 2 years.
However, if we are going to do so anyway, both the human and economic costs will be lower the earlier we begin.
If we allow exponential growth to continue with a doubling time of only a few days (even if we can move it from 2-3 days to 6 days), the time until this move is forced is very limited.