Storing important documents, like your home deed, birth certificate, and marriage record, makes sense because you don't typically need those in an emergency. But you wouldn't want to store some documents, like your living will or power of attorney forms, in a safety deposit box because your loved ones likely would need quick access to those documents if you become incapacitated. Instead, you'd want to keep them stored securely in your home and let a loved one know where they can find them.
The safety deposit box can be a good place for your jewelry and any other valuables, though. They're generally safer in the vaults of a bank than they are in your home, although if you need an additional layer of protection, you'll want to purchase separate insurance coverage.