It’s a lot easier to hide a piece of paper than it is to hide stacks of cash or gold.

Unscrew and hide behind a doorknob or a light switch, the inside of a clock, the bottom of a dresser, inside the wall trim, the leg of a couch, etc.

Then add controls on the wallet itself - only x can be withdrawn every 24 hours, and m out of n recovery methods (your trusted friends and family, a service which validated your email/ phone number, a pass phrase, an in-person office which validates your id and passport for a fee, etc), and you can be as secure as any bank.