Russia claims 95% effective vaccine with Sputnik V (1). This one is also based on a viral vector like the Oxford vaccine, and is also more stable than the mRNA viruses.
Assuming this is a safe product, it adds more to the bag of vaccines to stop the spread of the virus, and prevent further mutations. Preventing further mutation is essential to preventing more lethal strains from developing, and/or prevent the current one from evading immunity due to mutation. It does not matter if the immunity is from an infection or the vaccine. The virus, left to spread, will eventually evade all immunity, and return in some form. We don't want to find out what form that might be.
For those wondering about the value of a vaccine: The virus is lethal to many people. The vaccine is not. It will prevent fatal infections.
Whatever numbers you wish to quote, there is no doubt that a near-zero death rate from the vaccine is better than the considerable rate we are suffering without it.
This is not even a close call.