What is the lesson?

If something even slightly goes wrong with my software I don't want it to survive at all. This is the equivalent of putting dynamite on all the load bearing points of a structure, rigged to explode if they move out of place!

Software doesn't bend, it's digital.

That is something that is very context dependent. It is fine if it is essentially 'free' and of low criticality. But if you are dealing with an application where doing so would prove very expensive or cost lives it is clear that it isn't the ideal.

I'd say it's fine in the specific range where malfunctions can be expensive, but total failures aren't.

You pointed at one end of that, where the failure is equally expensive. From the other end of it, I attempt to build my Minecraft mod such that partial failures are transient and local, rather than bringing the entire game down.