If we put "cash in a hidden safe" at 1, I'd put "money in a bank" around 10. My checking account was once drained by the state on a clerical error. Or almost - they left me 17 cents. They did have a process to get it back (which, interestingly enough, involved emailing cryptographically signed documents back and forth), but it took a few days, and it was only lucky timing that prevented it from triggering a cascade of problems.

These newfangled experiments that I don't fully understand are still well above 10 for me, but they only have to get down to around 11-15 before I'll be interested.