For example, if I pull the door handle of my car, it directly activates the latch, and the only way that could fail is if something physically breaks or jams. It's not just a switch sending a signal to some "brain" in between that could just decide, deliberately or otherwise, to not honour my "I want the door to open" request.
People are often surprised to learn that, despite me making a living off software development, my daily driver is one that has exactly zero lines of code controlling it.
You're not choosing hardware over software, here - in which case I might choose differently - you're choosing to eliminate an entire link in the chain. That's always going to be a win for reliability.
I think we need a good term to describe this specific kind of trustworthiness.
I am not sure mechanical hardware is less likely to fail than software. For example, ford recalled door latches for a mechanical problem - https://media.ford.com/content/fordmedia/fna/us/en/news/2015... what is worse is my friend can't get the door latch replaced on her ford because "the part's on backorder."
This is why I believe there should always be a mechanical override for safety-critical features; locks, brakes, steering. I trust hardware far more than software.