When we first immigrated to Canada my family kept some of our documents such as birth records etc. It was super cheap and my family felt security was beneficial.

I don't have one currently but perhaps I should.

Most people in here are rich.

I'm middle class. We have a safe deposit box where I keep stuff that would be a pain in my ass to replace in the event of a fire/flood/etc.

Said items are titles to my vehicles and home, my marriage license, the will of a family member I've been entrusted with, birth certificates for my self and family members, and a couple of keepsakes for the kids that I'm very long on. It only costs me about $80 per year, and it brings me a lot of peace of mind. I have photocopies of all those docs at home, because you rarely need the real thing.

A local bank near us provides a free one as long as you keep $100 min balance. So ends up being very cheap offsite backup to store important documents, a backup hard drive of most precious data, etc.

They are really handy for storing backup hard drives too. Short of having your own armed guards and razor wire it is good physical security for free or cheap.