I prefer to use the trustee's watermark which reflects the value of Bitcoin after the price manipulation of fake Bitcoin being sold by MtGox had been taken out of the market at $460. But your point is made even stronger if you consider that same money could have been safely invested with a steady interest of 2-4%. And that's if you disregard that the sort of risky investments that that sort of play money could have gone to, nearly all of those investments have been extremely lucrative the past 8 years.