If instead, we all stay home and quarantine, the second we start reducing the quarantine the virus flares back up again. If instead, we start acquiring immunity in low-risk populations, at a rate that the hospitals can sustain, we'll have a degree of herd immunity and a portion of the population that can no longer spread it.
I'm certainly not an epidemiologist though; anyone smarter than me that can way in on that thinking?
A fair portion of low-risk people will require intervention. Given that a lot more people are low than high risk, you're still overwhelming the health system, and all those low-risk people are still going to interact with others while they are asymptomatic but transmissible.
Time means more ICUs, more ventilators. It means industrial capacity can shift from making consumer goods to medical supplies like masks. It means medical personnel get training and experience with the disease instead of shooting in the dark. It means labs and research teams can give more informed treatment advice.
It means small businesses and industries can try to reallocate resources and jobs and maybe save part of the economy. It means more time to educate the population to avoid high risk activities, wear masks, wash hands and so forth.
In every way it’s better if we delay the pandemic now that we know about it than if we just let it peak exponentially and kill the maximum number of people.