Seems the majority of bitcoinatics would turn into goldbugs if even the chance.
Few would recommend holding more in bitcoin than you can afford to lose. "All your wealth" is more than you can afford to lose.
I would go for gold. I'm very sure crypto-currencies will still be successful in 10 years, but I'm far less sure that Bitcoin will be the one. I'd guess there's a 20% chance it won't be, in which case it will probably crash to zero. Gold prices may drop, but not so low as that.
If the rules in the original post allowed me to transfer funds between different alt-coins during the 10 years, I might go for Bitcoin instead.
Why not buy silver? It's much cheaper than gold but still more valuable than fiat paper, Right now it takes about $21 to buy 1oz of silver.
That's at best irrelevant (since we have to hold it for 10 years), and at worst a liability as the weight and bulk of silver makes it harder to store and move high value amounts.
Also silver can be melted down and used to kill werewolves and that's something you cant do with gold or platinum.
I have to admit, that's part of the reason I have some silver.