Could be a big development. If 'healthy' people know they can catch Corona and even if symptoms get bad and they are hospitalised they are very likely to survive then its pretty much pandemic over. People will take the risk and get on their normal lives.
Particualarly if we also get conformation that if you've had it you wont get it again, or wont get it anywhere near as bad.
There is still an awful lot we do not know about long term heart, lung, and organ damage. While preferable to death, chronic heart and lung disease result in significant disability - and is not something I would consider an acceptable outcome
I personally would much prefer a medicine/cure rather than a vaccine
At this scale, a vaccine is a far superior option. If you can vaccinate enough people to achieve a herd immunity, then even the anti-vax hold outs will get some degree of protection against the spread. The vaccine can prevent people from even getting sick in the first place. A medicine is only useful once a person is sick, has possibly already transmitted the disease, and requires the use of the health care system.