With a couple of bad metaphors you can prove almost anything. But anyway, the point is blockchains (I guess). >Consumers actually like transactions to be rever

With a couple of bad metaphors you can prove almost anything. But anyway, the point is blockchains (I guess). >Consumers actually like transactions to be reversible, within reason; markets work better that way. Companies even like to be able to safely unwind legal agreements sometimes when it turns out those contracts weren't the best idea. Reversing financial transactions or contractual agreements in a way that eradicates all traces of their existence is almost never what you want and it is almost never legal. If there is one truly append-only world out there then it is finance and legal. I'm sure there are some exceptions, but it makes little sense to build an argument on those. I do agree though that blockchains seem like a rather contrived solution to some of the problems they are supposed to solve.