ex: https://www.cbc.ca/news/safety-deposit-box-protection-1.7338...
https://archive.is/www.nytimes.com/2019/07/19/business/safe-...
It's great if you want to store some documents. But don't expect _real_ security. It's guarded by a minimum-wage employee, and the keys are usually laughably insecure. Banks know this, so they cap their liability for the loss of the deposit box at around $1000.
So don't even think about storing gold bars there, like they do in movies.
There _are_ companies that provide safe storage for high-value items, but they are pretty exotic.