Not being beholden to a central authority (whether that authority be Twitter, PayPal, or the US government) is intrinsically valuable to a lot of people. Blockchains are just a convenient and proven way of enabling that sort of independence.
Granted, decentralization is a bit of a niche, and the cryptocurrency gold rush has made it way more mainstream than it has any right to be at this point in time given its drawbacks. But that doesn't mean it's not valuable.
As for blockchain specifically: yes, decentralized payments seems to be the primary use case. But once you have a decentralized payments system, that enables the creation of a whole bunch of other decentralized applications that would not have otherwise been possible. That's why most "blockchain" projects start with a currency and then build from there: it's hard to build decentralized cloud storage[1] or decentralized DNS[2][3] without first having a decentralized way to pay for those services.
[1]: https://sia.tech/