TIDAL is a music streaming service built around music streaming with an emphasis on higher-quality audio formats and music-first listening. In practical terms, it is sold as paid subscriptions rather than a mainstream free-tier pitch, so the product is not just the catalogue itself but the way the service packages access, apps, features, and account rules around that catalogue.
The point most consumers need early is that TIDAL is an access service, not a permanent ownership product in the old retail sense. You are paying for the right to use the service on supported devices under the current plan rules, not buying a library that sits outside the platform altogether.