It's a matter of considering the alternatives, the major one taking a chance with the virus itself.

Also, it's not clear where you're getting that 'at best 5%". The sample of the population that they're testing against seems fairly representative. Are you looking at biostatistical factors not considered? If so, what?

On the plus side, as an mRNA vaccine, we're unlikely to have a 'Cutter incident'.

Given that it's not yet clear if either of these vaccines also block transmission it may not make sense to give the vaccine to non-high-risk populations until that is settled - and once it's rolled out to health providers and other high-risk populations, we'll have a better sense of transmissibility in the immunized.

Liability is a separate issue. Vaccines tend to be low-profit, factor liability in, and nobody would be willing to make them.

That said, this is mRNA, so it seems the worst that can happen is a lack of efficacy.

And as far as 'long term track record', many/most old-line vaccine producers got out of the business because of liability (see above).