The population at risk being vaccinated was the big deal, but that's done now (apart from those who refuse to be vaccinated, but then it is their problem).
They are less likely to be infected, and it looks like they have a shorter infectious period.
Herd immunity may be achievable with this in mind, but no one really knows right now. New variants may change the calculus too.
https://www.businessinsider.com/delta-variant-made-herd-immu...
It is not a binary 0 or 1 as far as if vaccinated people will spread the infection if they are infected. The vaccine lowers the chances, so the more people we can get vaccinated, the lower the chances can get.