Yes, to prevent mild cases the vaccine demonstrated efficacy. But who needs to take the risk of this drug with a yet unexplored safety profile, just to prevent a mild flu-like diseass?
For severe cases there was no proof yet, per protocol, for efficacy. It is not scientifically sound to say "but it might work" if you don´t adhere to the analysis you have committed to initially.
And regarding the 7 days, so you would then also take only one shot, if that "seems to work as well"? Some might take one, others 2. This will create a chaos. Either the correct dose regime or nothing at all. I still prefer 0 doses, I don´t want to mess up my immune system for nothing.