If the long term effects put a lot of people in the hospital, than that would not be the ideal outcome. You can't just drop clauses out of my definition of "ideal" then turn around and tell me about how that's not ideal. I agree, actually! Something other than the ideal I described would in fact be less than ideal!
The point remains; on its own merits, the ideal would be that it turns out everybody's already had it, because that would prove that the currently-known negative impact is also the total final negative impact. Since the total known negative impact is basically a given and can't go down and is thus a minimum, finding out that's also a maximum would be good news. On the whole, more people having been exposed without hospitalization or even awareness is good news. Maybe earlier in the cycle that wouldn't be the case, but with where we are now, it is.
At least, for this pandemic, for a disease that happens to affect a small set of people badly but, to all evidence, most people not at all. In terms of weathering a pandemic in which it was actually bad news for a majority of people, this has been a rather disheartening experience. That's a problem for another day, though.
(Which is not a synonym for "not a problem at all". But it's a problem for another day. Trying to solve COVID-19 with measures appropriate for EvenMoreBubonic-2022 is not a win.)
Please remember that we still know little about this virus, about long term effects, about how long immunity lasts, about the risk of auto-immune responses etc.
It's never, ever a good idea to let a new disease spread along the population of you can help it at all.