Primarily because it is the pioneer of the blockchain technology, and the world sees through the benefit of the latter even sans Bitcoin per se. Now, what I see is happening is that people use the price of Bitcoin as an edge among other competing cryptocurrencies. (You have to admit at some point that its price is really enticing especially to people who are aggressive in terms of investing.) Hence, if you are not an aggressive risk-taker, this business is not for you. And if you are, you will greatly benefit with the unpredictable highs in the market.