Traditional #fiat currencies work because each one has in parallel a more or less extensive market where it is used and accepted. The value of money depends precisely on that acceptance.
In contrast, the concept of cryptocurrency is intrinsic to a #blockchain. The two cannot be separated because the former are not really currencies (the name is misleading), but essential parts of a blockchain through which #value is transmitted.
The #NetworkEffect is a phenomenon whereby increased numbers of people or participants improve the value of a good or service in an exponential way.
The network effect is intrinsic to a blockchain: the more participants they have, the more efficient they are. And the more efficient, the more participants they attract.
Every investor who decides that #Bitcoin (or any other cryptocurrency for the matter) has value increases the value of the underlying #network.
This does not happen in conventional money or stock market bubbles. For example, a buyer of Microsoft stock does not increase the company’s long-term cash flow.