From Nintendo.com/us:

Virtual game cards make digital games even easier to use
The virtual game card feature for Nintendo Switch and Nintendo Switch 2 systems adds some of the flexibility of physical game cards to your digital game library!

If you have two systems, you can digitally eject and load games from one system to another—and you can even lend games to members of your Nintendo Account family group.

I don’t know if this truly makes digital games “easier to use,” because it seems like it’s actually creating and solving a whole new problem, but okay! Sure!