I agree with you on both points. And also about the error bars - I don't think I can "prove" cryonics to be pointless.

But one has to make decisions based on something. I would rather build a school in Africa than have my body frozen (even though, to reiterate, I'm all for living longer, and I do not believe that death has inherent value).

Biggest obstacles are membrane distortions, solvent replacement and signalling event interruptions. Mind is not so much written into the structure of the brain as into the structure+dynamic activity. In a sense, in order to reconstruct the mind within a frozen brain, you would have to already know what that mind looks like when it's active. Then you need molecular tools which appear impossible from the fundamental principles of physics (uncertainty principle, molecular noise, molecular drift...).

My view of cryonics is that it is akin to mercuric antibiotics of the late 19th century. Didn't really work, but they were the only game in town. So perhaps with further research, new generation of mercuric substances will be developed which will solve all the problems, right? In reality, a much better solution was discovered. I believe this is also the case with life extension - cryonics will fade away, and we'll move in with a combination of stem cell treatments, technologies to eliminate certain accumulated toxins (primarily insoluble protein aggregates and lipid peroxidation byproducts), and methods to eliminate or constrain cellular senescence (I'm actually willing to bet ~$5 that these are going to be the first treatments to hit the market).