I have had contradictory information on this - do I really need to have my PS4 game disk in when playing FFIV?

A message asks me to insert the disk when I try to start the game, but others with a hardcopy say they don't need theirs. It's just a minor annoyance but I can see no reason why I would need it - having already used the code to play the game it's not needed as proof of ownership or anything. I can play my Windows copy without needing to use the disk.