Is there evidence that we can expect a benefit? Could we put a probability distribution over that?

In other life and death fields, like medicine, the promise of saving lives is made all the time, but even for great benefit we do not cut corners to prove benefit more quickly.

Given the way that automobiles have little regard for life, I would rather that we take our queue from fields like medicine that have bothered to deal with the ethics and the cost benefit analysis.

Similarly, your claims about COVID reactions not weighing the cost benefit analysis are unfounded, at least that I have seen. I have seen many self-motivated parties making ridiculous, absurd, and harmful suggestions, but nothing that could be taken intellectually seriously. It's just people scamming for their own personal gain at the expense of others' lives.