When we talk about the value of X, we are not referring to the technology which is used to exchange, transfer or store X, but we are referring to the practical utility of X. If X is some tangible good, this practical utility is the ability of X to satisfies some human want or need. If X is representative money, this practical utility is the legal ability of X to restore ownership rights of some tangible goods. Bitcoin has none of these abilities, and thus it has no value - it is just an empty numerical value.
Bitcoin technology is simply means to transfer or store numerical values. There is nothing valuable is the ability to transfer or store numerical values. The whole system is just a modern day ponzi scheme.
Cryptocurrencies have value because people think so, true, the same with fiat. I guess you would have heard about Cowry money or Rai Stones, in the same sense these empty numerical numbers are perceived as money/valuable by the crypto community. At that time the Island of Yap had no fiat system or any currency so they came up with Rai Stones and agreed to give it value and used it as a tool for trading goods and services. Now every country have their own monetary system/policies so today simply empty numerical numbers shouldn't make much sense or have value? Isn't it? There has to be something that makes it different/unique. It's the decentralized Blockchain technology and you don't want to refer to how a distributed ledger based peer-to-peer value transfer system has no utility, not including the unique properties of a few cryptocurrencies. There is value in the ability to save, move, or store numerical numbers in a decentralized, censorship-resistant, trustless, peer-to-peer system. Speculators will abandon when/if price of cryptocurrencies drop sharply, but the ones who believe in creating value in a decentralized environment, don't think would let the cryptocurrencies collapse soon.