I really dont see BTC being around in 5,000-10,000-25,000-2 million years. Do you?
Gold will be laying or being worn somewhere.
I'm not sure I even believe humans will be around 2 million years from now. All that matters to me is the next 20-50 years. This guy isn't trying to pass on the wealth to his descendants 5,000 years in the future.
In 5,000 year, I expect gold will be a by-product of our cold-fusion reactors. There'll be more of it than we know what to do with. There will be landfills full of the stuff.
If gold has any value in the distant future, it will be manufactured. Completely silly to think gold is a good store of value for the next 25,000-2,000,000 years.