If I'm the user - whom I mostly trust - there's nothing wrong with my data.
DO you trust yourself?
I trust myself to not try and actively exploit or sabotage my own systems. I do not trust myself to always get things right -- coding defensively and making things fail gracefully, avoiding unexpected and potentially dangerous behavior, is a good thing!
Avoiding the shell (unless you have a good reason not to) is like useing strict. Yes, I trust myself, but I know I'm not perfect, so I'd rather have that extra safety net.
(There's also the question of whether whoever is at the terminal, logged in as you, is ACTUALLY you, but in my case that's a lesser concern.)