Warren Buffett is not a fan of Bitcoin, Marc Andreesen blasts back

Warren Buffett was on Squawk Box and was asked about Bitcoin. Apparently he isn't a fan. He said it's a "mirage" and "stay away". Marc Andreesen fired back on Twitter, saying that "Warren has gone out of his way for decades to avoid understanding new technology. Not a surprising result." 

This Buffet guy, what does he know about money anyway?