Clients with access to Apple's Global Service Exchange (GSX) service are able to use the API to enrich calls to this endpoint with additional data on device status. This allows clients to look up colour, model, capacity and lock status data from an IMEI, which is valuable.
We cannot provide direct GSX access to clients without a valid Apple account (reselling access is not permitted). Once clients have GSX access, we can help them query GSX and augment its data with our own rich set, in a way that supports their own processes for repair or servicing.
Clients working with GSX will need to exercise caution where they allow their end-users to access this data, as it must be protected from scraping by numerous "IMEI lookup" tools that exist, which seek to provide this data in violation of Apple's terms.