Diversifying enough to live decently if Bitcoin fails but no way 50%. If Bitcoin succeeds and becomes a stable currency it still makes a lot of sense to hold bitcoin. It would be a non-inflationary currency that grows in real value in step with general economic growth. That would make it the optimal investment as long as you don't have private information about other investments, as such information is the only way to beat the index (i.e. overall economic growth) on average.