Not in a person-to-person basis, obviously. Lots of people were having mild cases before, luckily. So it's also obvious that some people will continue to have mild or even asymptomatic cases without being vaccinated. But looking at the whole population, we can very clearly see how severe cases decreased from "enough to derail the healthcare system" to "pretty much no one".

It does little to stop transmission with the newer variant, true. It does, however, a lot to stop fatal or long-term cases, though, which was literally the point.