Currently Online 
For me, personally: Because it needs a download and a game card to work. With a physical card, I put the card in and play the game. With a download, I need to have the game installed but I don't need a card. With a GKC, I need to have the game downloaded and have the card with me at the same time.
Download space is precious on consoles, often your console will only fit a handful of games at once. Final Fantasy VII Rebirth will apparently be over 100GB in size on Switch 2. So the internal memory would only fit two games of that size. Even with my 256GB SD Express card, I could only fit four to five games of that caliber at once. And now I need to have these games downloaded and have the card ready to play them.
If the GKC only needed to be popped in like once a month to verify the license or something it wouldn't be that bad. Right now, the only advantage to GKCs is that you can resell them, which you can't do with a digital copy, of course.
