Seriously! A digital key is NOT easier to secure than a physical one. If anything, it's harder.
Gold only becomes hard to store if we're talking about huge quantities
Or etch the key on a piece of metal, seal it in plastic, and throw THAT in the ground, if your are that way inclined!
I don't see the difficulty.
The advantage of bitcoin is you can encrypt it and store it offline in as many locations as you want.