The one example I can point to where maybe existing systems were improved through blockchain-like technology would be Certificate Transparency https://certificate.transparency.dev/howctworks/ yet even then there's a lot of trust in browsers run by centralized actors to ensure the system works as expected. The system is further documented in https://chromium.googlesource.com/chromium/src/+/refs/heads/... and https://www.rfc-editor.org/rfc/rfc6962.html Also, https://blog.cloudflare.com/introducing-certificate-transpar... is a good read.