1-2 Switch is a game that's only really useful in a party setting. It's not the kind of game you can just bust out any time your with a friend, there has to be a crowd involved. It's something mainly makes sense in Japan, which is why the game still gets advertised there. Besides, 1-2 Switch isn't a pack-in because it doesn't actually explain what the Switch is on a broad conceptual level like Wii Sports did with the Wii.
lol, pack ins don't have to explain a device.
Usually, they do. Unless it's a specialized bundle. A standard pack-in title for a console should explain exactly what the product is, and why you should care. Tetris explained that you can take NES quality gaming with you on Game Boy. Sonic the Hedgehog explained that the Genesis was a faster, cooler, and more mature system than Nintendo. Wii Sports explained the Wii was simple, motion controlled fun that's good for people who never played games before.
1-2 Switch doesn't actually explain what the Switch "is" on that kind of broad level, it only shows one aspect of the console. Hence, it's not a pack-in. The Switch is a home console you can take with you, thus if Nintendo wanted a standard pack-in for the system, they would've needed a game that demonstrates all the functionality and potential the console has in one game. Taking home console gaming with you, Sharing the Joy-Con, the Touchscreen, Local Wireless, HD Rumble, Motion, the IR Camera. 1-2 Switch only really shows 3 of those features. Again, it shows the party potential of the platform, but little else.