The discussion of at what point vaccines allow life to return to normal often seems confused to me. The effect isn't sudden at the point that we reach herd immunity — rather vaccines allow a gradual loosening of social distancing.
Imagine that the R back in February were originally 3, and now is hovering around 1 thanks to social distancing and other measures.
Once 10% of the population is immune — whether via vaccination or infection — we can keep disease rates low while engaging in behaviour that would otherwise in February have led to an R of 1/0.9 = 1.11.
With 20% immune via vaccination or infection we can return to a level of social contact that was previously consistent with R = 1/0.8 = 1.25.
And so on, right up until (1-1/3) = 66%+ of the population is immune and we can return to normal February-style life.
Basically, the faster we vaccinate, the faster we can open things up without seeing the coronavirus run out of control.