It’s the cost when something fucks up.
If I’m holding my phone near a cliff, and I rely on it for navigation and I’m hours from civilization, I’m a little more careful, not because I’m normally super careful. It’s because — in that specific scenario — losing my phone would cost me so much and the chance of it happening is much more likely.
Space companies spend a little extra because the cost is years of development and billions of dollar evaporating in a few seconds.
And there are software teams in certain industries that dot their I’s and cross their T’s as well.
Even on some dumb CRUD app, if it’s a critical piece of code that the rest of the software hinges upon, you spend a little extra time because the cost of fuck up is so major.
Or you’re launching a product and you have a sign up that will seed your user base, you damn well make sure it works.