Here’s how Nintendo explains the lounge’s function:
Players have been able to use the Online Lounge feature of the Nintendo Switch Online app to arrange Splatoon 2 online battles using their smart device, such as by sending a URL link that allows social media friends to join a room.
Once the invitations are accepted, the icons of your friends show up in the Online Lounge. The mode allows only for private battles between those present in the lounge.
The function has only been used for Splatoon 2, and it doesn’t seem like a widely-used one, so I don’t think this feature will be missed. (Most players probably organize online sessions through other platforms, such as Discord.)
Back in 2017, Kotaku checked out the then newly-launched Nintendo Switch Online app when it hit Android and Apple devices. Chatting seemed fine, but there were issues with the app. At the time, our own Mike Fahey wrote:
It’s better than nothing, but not much better? It would be just as easy for players to call each other on Skype or Teamspeak or whatever they did when they played the original, completely voice-less Splatoon. If we’re going to require external hardware, might as well have full-featured software to go along with it.
An optimal solution for online voice chat on the Nintendo Switch would be the ability to just hook a headset to the console. Instead, Nintendo decided to require players to use an external app on an external device.
Read his full impressions here.
Nintendo explains that while the Online Lounge feature will be removed, the app will continue to allow voice chat, adding that, “no other changes will be made to the app at this time.”