-Warren Buffet
This quote is constantly bandied about as justification to invest in Bitcoin, and especially now that there has been some nice price movement in the upward direction. But this Warren Buffet quote is only relevant with the proper context, which is that Warren Buffet only invests in things he has a fundamental understanding of and can quantifiably value. You can confidently be greedy when others are fearful if you have a sound investment thesis and are a fundamental value investor. This is how he turns his investments into home runs, he knows what he's buying and what it's worth and can weather the negative sentiment until the market learns what he already knows. This doesn't apply at all to a speculative investment like crypto. Following this advice willy-nilly is gonna get you burned because you're misunderstanding the intent and the application.
Don't not buy Bitcoin if that's what you want to do, but don't fool yourself into thinking you're following Warren Buffet's advice. Warren Buffet doesn't speculate, and if you're buying crypto, you're speculating.
Keep in mind, the price is what you pay, and value is what you get—pay too high a price and returns are decimated. To elaborate on this, the value of a stock is relative to the amount of earnings it will generate over the life of its business. In particular, this value is determined by discounting all future cash flows back to a present value, an intrinsic value. Pay too high a price and the return that arises as a stock gravitates back to its intrinsic value over time will erode. Act greedy when others are fearful and reap enhanced returns, under the right set of circumstances: predictability must be present, and short-term events that create the subsequent downgrade in prices must not be moat-eroding.