The problem goes down to Hanlon's Razor. In elevator or airplanes, it applies, we try to make as safe as possible, we ironed most of the bugs (over which the m

The problem goes down to Hanlon's Razor. In elevator or airplanes, it applies, we try to make as safe as possible, we ironed most of the bugs (over which the maker would lose big), and if they ever fail, would be far more possible to be because human stupidity than malice. In the other hand, with voting is human malice what matters. The holy grail for that is to paint it as safe and failproof as possible while still rigging things for the intended party at some point of the circuit. And there is big money to ensure that it happens, so the for profit manufacturers of such machines (or their for profit workers/managers) will be very motivated for slipping a subtle/obfuscated bug or backdoor somewhere (remember the Apple SSL bug due a duplicated goto fail line?). Making software safe from their own makers is complicated. Software itself it runs may be complicated, what makes auditing it not trivial, and with enough resources you still can play with lower layers like the compiler or chipset (for all or a portion significative enough of the machines). And blockchain is a tool that can be misused too, we already seen a lot of frauds, scams, majority attacks and so on over it. "It is safe because it uses blockchain" is a good intro by someone that have something to win there.