Sort of... They are used at scale to share and ingest data between services, for things like recommendations, etc. But it is messy, a lot of the ontology is more or less the same but every company/database does things slightly differently.

Most of the difficulties are with matching artists and content across different databases, which is a separate issue. The ontology itself is tangential, but one example where it's important (even if it's not a fully / cleanly solved problem).