There's certainly application outside of currencies. Bluesky/atproto for example is built on DIDs (decentralised IDs) and IPLD (the data format/standard of IPFS). Both are very heavily rooted in cryptocurrency tech.
There's a joke in the atproto community that it's a blockchain but without the currency because of this.
IPLD is literally a merkle tree data structure format standardised by IPFS which is heavily rooted in cryptocurrency and in fact has its own cryptocurrency created by the IPFS devs: Filecoin.
DIDs were created by cryptocurrency orgs. The standard was created by a bunch of cryptocurrency groups working with the W3C and the entire time it was being developed, it was derided by non-cryptocurrency people as just another way for cryptocurrency to scam people. It doesn't stop being related to cryptocurrency once you realise it's useful.
