The vast majority of people are still vulnerable to coronavirus. It's only the current restrictions that are preventing more people from dying. A vaccine would teach our bodies to fight the infection by stopping us from catching coronavirus or at least making Covid less deadly. Having a vaccine, alongside better treatments, is "the" exit strategy. Why do we need a vaccine?
For countries that things are too far gone as it is ... cough the US... it really is best for the healthcare workers and at risk folks. I honestly think the development of the new vaccine is pretty cool. In comparison to other vaccines that took years to develop, this one should be =<1 year which is crazy.
The point of a vaccine is to find a cure and stop the spread. Once a lot of people take the vaccine, the immune system can fight it off earlier making everything including the infections rate downfalling