> Barring gross negligence or malice, most things go wrong for reasons other than the immediately involved actors.
Anytime I hear of systems failing, I can't help but think about Dr. Cook's paper on How Complex Systems Fail - http://web.mit.edu/2.75/resources/random/How%20Complex%20Sys...
My experience is that asking five whys can help you manage or mitigate some of the root causes. You probably won't get them all on this pass, but if this is important, it'll come up again and you'll try some other root causes. However, if you think you've found the root cause, you're probably wrong. I dunno about "terrifying", but accumulating scar tissue can definitely create more problems than it solves.
"How Complex Systems Fail" http://web.mit.edu/2.75/resources/random/How%20Complex%20Sys...
A no-cash system, beside all the other downsides, reduces and sometimes outright removes the ability for humans to alter and/or workaround the system when systematic failure modes are discovered. And that's just unintended consequences, forget about perverse incentives.
This is the same reason I think augments that posit privacy is unnecessary because enough downstream controls will somehow account for all "bad" things that could happen. It's a scam, pushed by unscrupulous hucksters for their advantage at the cost of everyone else.