With how games work these days, having just the disk is pretty much useless if the publisher decides to delist or discontinue the game from platform, because:

• patches and updates don’t come with disk form anymore.
• many games that requires online authentication to play won’t be available to keep playing if their account service is down.
• games go on sale with steady rate most of the time(except nintendo), for bargain bin deals you would probably find the game on humble bundle or gog.
• you often have the good games that release “better” remake version over and over anyway. Note, I know people sometimes prefer the original version, but not everyone is on the same page and it hugely depending on the dev/publisher for the newer version.

Now let’s describe the cons:

• in many countries, breaking DRM is illegal. So even if all you want to do archive, you can’t make a decrypted copy. That’s why homebrew etc provides the key/dumper for you to do such at your own risk. IMO, it’s safer(INAL) to download pirated iso/rom compare to doing your own dump. And, archiver actually tried to keep a post patch version before store is closed down(see wiiu store close example), the disk version is not a viable option anymore for archiver.
• storage up keep, physical things require storage space. I still have like 3 large shipping box for my older gen(ps3/GC/Wii/X360 games) I will probably donate them to library or something and keep the only ones I wanted to keep.
• console part cost, the BD drives are often first point of failure, then HDMI connectors. Cause well, moving parts are easier to break and harder to QA. PS5’s 2 versions gives a good example how the disk affects the look, weight, etc. Not to mention, they are a lot slower then SSD and you are required to install all that anyway.
• developer/publisher/platform see nothing for used game sales. It sounds like huge shill talk but let’s be honest, they want to make a living, if you are not supporting your favorite developer they will have to offset the cost by doing shit you all won’t like. ie, mtx, subscription service, selling analytic data, selling the studio to shit publisher that push worth practice, platform raise price to meet target projection. Buy/sell used game only helps that service owner(gamestop/ebgame/bestbuy, not the community.)
• did I mention switching disc just to play game is a PITA, and if your case is the modern garbage version, remember those plastic break down more easily and you would have to buy new case to hold your disc.
• environment waste for all the manufacturing, packaging and shipping. It’s honestly not worth that in modern era if you give a fuck about how future generation will live.