Or, if a dilettantish crypto app provides a false sense of security to political activists, which may be life-threatening as well, depending on their country.

Dialysis machines are really crappy compared to kidneys. And first dialysis machines were worse again

> But if a dialysis machine breaks

That's why we have standards for medical devices. A minimal implementation would still need to adhere to the required standards.

Worth doing badly as opposed to not doing it at all, ie you have to start somewhere even if that turns out to be inadequate later.