Declining severity is good, but it's not that important. Case count has the potential to increase geometrically if we're not careful. If the case count is doubling, say, every week, then a huge 75% decline in severity only buys us two weeks.
It is IMO, because the mere fact of being infected is a necessary, but not sufficient condition to cause problems. What matters is being infected and needing hospitalization (which as far as I can see not clear cut and heavily dependent on the place of spread).