Some might argue that a "great store of wealth" should not have high volatility. But regardless, I do believe that 2018 brought BTC into the mainstream of finance, investment and savings, as a vehicle in the considerations and calculations of wealth.

Some time back, perhaps around 2005, gold became accepted in investment portfolios. It came to be accepted that some percentage, such as 5-10% in hard precious metals, was not unreasonable.

I believe that's where we're headed with "digital gold."