For a long time I have bought the digital versions of movies off of iTunes and have more recently been expanding my physical collection. I’m curious, how big is the difference between the 4K digital version of a movie compared to the actual 4K disc? If I own the 4K digital version of a movie is there any reason to also pick up the disc version?
Biggest difference in audio quality, especially with regards to bass. The best example would be scenes with gunfire like the opening Opera Siege sequence of Tenet or the batmobile chase in Batman (2021).
However not all movies have that big difference - if you have heavy dialogue or if there was little effort put into sound design then you might as well stick to digital.
As a guide, if the sound quality was excellent in the movie theatre then i would put down money for 4k disk.