A BR disc contains much more than just video data. The BR player device contains user-hostile functionality.
For example, firmware updates for various parts of DRM, like HDCP key revocation lists, are distributed with commercial BR discs.
Your playback setup could become permanently broken because you inserted the wrong movie and now your player refuses to send a video signal to your TV, or it suddenly stops accepting discs it did before.
A BR disc contains much more than just video data. The BR player device contains user-hostile functionality.
For example, firmware updates for various parts of DRM, like HDCP key revocation lists, are distributed with commercial BR discs.
Your playback setup could become permanently broken because you inserted the wrong movie and now your player refuses to send a video signal to your TV, or it suddenly stops accepting discs it did before.