No cryptocurrency has ever attempted to produce anything other than, arguably, more cryptocurrency. The only way to make money on it is to find someone willing to pay more for that intrinsically unproductive asset.
You are both right and wrong about something... currency can be unproductive. What good does it do to stick money under a mattress? But currency is incredibly valuable to society, because it facilitates exchange, trades, and economic activity. When it's easy, and cheap, it's easier to do business, and easier to be a consumer. It's easier to trade your time for food, to convert a used car into a tuition payment, etc. The cool thing with some cryptos is that they are being used to facilitate other kinds of activity.
The helium network pays individuals to set up a decentralized wireless network. It's now the largest long range network in the US.
Self executing smart contracts built on block chain networks are facilitated by the exchange of crypto. Reduces transaction costs on some transactions that require 3rd parties to oversee it.
Being able to hold your networth in your head (via a seed phrase), without having to carry confiscatable currency or cash, is very valuable to a people fleeing a war torn area (Ukraine), or somewhere with strict currency controls (Russia, Argentina).
Being able to send remittances to family abroad, for pennies in transaction fees, is a service that costs much more money today.
Ironically, the permanency of the transaction record could reduce money laundering in ways that a cash economy makes difficult. See the NYC couple busted in the last month.
The next path I see happening is on cyber security applications, including in the sharing of healthcare information.
I'm not very excited about NFT markets for art, but some people are.
There are many applications if you look around. This comment reminds me of someone snarking about amazon back in the mid 90s... "Why would I buy a book on the INTERNET when I can just go down to the bookstore and talk to someone about what books are good?" We don't know all of the different paths that this class of technologies will take us, in the same way that we didn't know where all of the paths that the internet would lead us. We didn't know we'd be walking around with handheld supercomputers that can send and receive live video around the world... it's changing how wars are conducted, how businesses find customers, and how employers find employees.