The Nintendo Switch Online app has positives, like Splatnet 2, but it's fair to say that the voice chat component has drawn a mixed-to-negative response. It does actually work, but it's a far from optimal scenario and has a number of quirks and drawbacks.
It's arguably an indictment of the functionality that companies are stepping in to offer alternatives that support wireless headsets. As it stands officially licensed accessories deliver a mix of wires, so the UNIOM Wireless Adapter aims to mitigate that with its own solution.
It's a Kickstarter pitch that has failed to truly take off in its earliest days - we'd suggest the somewhat low-key video isn't helping matters. On top of that, we suspect most are using familiar alternatives such as Discord due to limitations with Nintendo's app.
The existence of crowdfunding campaigns like this highlight, along with all of the social media chat and YouTube videos, the rough start for the official Switch app. Improvements are certainly needed.