One persons opinion does not necessarily affect the whole cryptoworld. If you are scared and dont believe in bitcoin nor the other cryptocurrencies then sell your coins but to those who are loyal to bitcoin and the alternate coins, they will stay and hodl and wait for the right timing for them to sell their coins when they need them and not because one person says it is the end or it wont end well.
Warren Buffet is a traditional investor, and has no technological understanding.
This is one possible scenario for bitcoin. If he has the right mindset and knows the potential of the company, he will invest in it in the early days and not when the stock is already priced high. I think in its meaning it bases on the end of all the currency that is not centered and still not seen. I am fully convinced that his prediction will prove false.