Bitcoin has value because it can do things that no other money can do. It won't drop to zero because people need it for things they can't get anywhere else.

If you want money that can't be seized, can't be frozen, can't be manipulated, Bitcoin is your asset. If you want to be able to send money across continents, bitcoin is your asset. If you want to hedge against USD risk, bitcoin is a great choice (very very different fundamentals, and almost always rises with political instability). Some people want that badly enough for at least some of their portfolio that they are willing to accept the volatility risks.

The volatility is a detractor, but that definitely doesn't mean it's good only for speculation. Bitcoin keeps coming back crash after crash because there is real value in owning some.