For what its worth, BD also holds the advantage of greater storage space (for more extras) and BD-Live for downloadable content. They might not be huge advantages, but they are something. So that gives
1)Better picture quality
2)Better sound quality
3)More storage for extras
4)BD-Live
You also have some other minor things, like picture in picture and interactive menu's during playback.
Owner of PS4 Pro, Xbox One, Switch, PS Vita, and 3DS