Shenobie makes a good point in his post defending Warren. It should be noted that, even though he lacks some up-to-date tech savvy, Buffett has real proven financial wisdom that has yet to be enunciated. One thing that he alluded to in cautioning against new, non-physical investments was that they come with unique risks such as a higher likelihood of volatility and intrinsic tendency toward early demise.

Bitcoin has already proven to have huge volatility and serious technical problems such as difficult expansion. More importantly, many experts and bloggers agree that Bitcoin has inherent qualities that are likely to lead to relatively speedy megacrash with Tulip Mania qualities:
https://en.wikipedia.org/wiki/Tulip_mania