Remember Friend Codes? Those used to be a thing back on the DS and Wii, where each user would have a unique Friend Code generated per game per system, that they would have to share with their friends to be able to play online. Things became slightly better on 3DS, which had only one system wide Friend Code, while Wii U removed them altogether.
For some reason, the Nintendo Switch adds them back. The day one update adds the option to add friends via Friend Codes- and seemingly keeps this as the only option. Apparently, you can’t add people using their MyNintendo IDs to search for them (though your MyNintendo friends from Miitomo and Super Mario Run are carried over).
It does seem like both parties involved no longer have to input Friend Codes to be friends- one can input the code of the other, and you automatically get a request which you can accept. But this is still annoying and disappointing, and makes it clear that full online parity with the competition is still not something Nintendo is looking at.