Physical PS4 to Digital PS5 upgrade

so I bought a sealed copy of Yakuza Like a Dragon for PS4. I guess the print run for the PS5 version was pretty small and now it’s overpriced. I saw that for some physical PS4 games you can upgrade for free to PS5 but it turns your physical copy into a digital one. My fear Is that I get a digital copy that needs a disc to play, what if something happens to the disc? Do I have to buy it all from over again? I have a PS5 Pro so I’m sure the PS4 version will look fine. As a pretty strict physical enthusiast, this doesn’t seem worth it. Any thoughts?