It’s not sharing. It’s just making it searchable - aka the catalog and link back. The second feature is the ability to continue/resume from the Home Screen. That requires sharing playback information. However, there’s no indication that Apple mines this information. On the other hand, it’s extremely useful to me as a user. This is the primary reason I don’t use Netflix much these days and I have a premium subscription. It’s so easy for me to reach to HBO Max or Hulu than Netflix.