In an interview with Gamespot, Reggie Fils-Aime has detailed the process and reasoning behind Nintendo opting to use smartphones for matchmaking, creating lobbies and voice chat.
“The smart phone app that we’re creating, that will be part of our online service, we believe is going to be a very compelling part of the overall proposition because that’s how you’ll voice chat, that’s how you’ll do your matchmaking, and create your lobby. We also think it’s a very elegant solution because if you’ve taken your switch on the go, you’ve put yourself in a hotspot, you’re looking at get a quick match of Mario Kart in, to whip out some sort of bulky, gamer headset is a bit of a challenge.” said Fils-Aime
“So we think we’ve got an elegant solution. That’s a very specific answer to your question.” continued Fils-Aime.