I thought the central point was the porn played on a loop. Maybe I was distracted and missed the real plot. Also maybe mixed up by the fact that one of the principle actors died in real life while the movie was being made.
The actor was Natalie Wood, and the event is shrouded in mystery about how she died. However, the character who dies in the movie is played by Louise Fletcher.
The porn and the vicarious near-death-experience were just plot points.
The author of the screenplay, Bruce Joel Rubin, is a self-described spiritual teacher, and "transitional journeys" is kind of his thing. His three most well-known films (Brainstorm, Ghost, and Jacob's Ladder) are all about characters experiencing the afterlife in some way.