Google is wrong in that regard, they are quiet different. You install a PS5 disc directly to you hard drive. No online connection required. For patches etc. you need a online connection of course, but you have a choice as a consumer. You have no choice whatsoever with keys and key-cards etc.
Right, the person complaining about key cards was specifically complaining about 2 things:
1) They use up memory
-This is just like PS5 physical media
2) Even after you install them, you still need to constantly put the card / switch the cards around every time you switch between games
-This is also just like PS5 physical media
So the main difference here is just compared to Switch 1, where you could actually play games off the cards, but that is largely a product of its time (for example PS2 games could run off discs because drive speeds weren't magnitudes higher than disc speeds at the time).
The fact that games now depend on GB/s read speeds and insanely fast random seek times, means that's not feasible anymore, in any way that is practical for physical media. Sure you could argue not every game needs to read/seek at those crazy speeds, or that the "EX" memory cards exist for that very reason, but I guess the issue is cost. There's no technology or media that is affordable AND can operate at those speeds.
So simply put - there is no longer any mass market path for physical media on newer games that is as cost effective as it was in the past. And yes, I realize CDP Red put Cyberpunk on a memory card playable, but I've ready countless responses that simply isn't feasible for small games and that Nintendo is to blame somewhat, for only offering 64GB cards and nothing else. But I still believe even without that barrier, the added expense and total lack of viable options for physical media to run off the disc/card at TB5 speeds of 40-80GB/s or whatever has created a roadblock for modern games.