I think you missed an important one, which is: how much do bugs even matter?

A bug can be critical (literally life-threatening) or unnoticeable. And this includes the response to the bug and what it takes. When I write code for myself I tend to put a lot of checks and crash states rather than tests because if I'm running it and something unexpected happens, I can easily fix it up and run it again. That doesn't work as well for automated systems.