By skyforbes Game Key Cards are Nintendo's way to have a retail presence… have a copy of a game that some can trade, lend or sell (instead of having a code in a box).
Nintendo is keeping their games on physical cards, but providing options shouldn't been seen as a negative.
There is no perfect solution as other handhelds do not use carts. With a Steam Deck, an Xbox Rog Ally X, Legion Go, the only option is digital games with no retail presence. Nintendo has done what it can to appease physical gamers, specifically parents or children buying games at retail stores.
People get worried (which is fair) about Nintendo closing the servers in the future, making VGC worthless, but this is just assumption. It is the same situation as a digital game, and Nintendo has never shut down their servers. To this day you can still download your Wii games from the digital store.
And my question is: With rumors the PS6 having an additional handheld version, how Sony could solve the issue of bringing the same physical retail games to the handheld? Will you complain if they offer only a digital version?