They're probably thinking of it in comparison to the Apple Pro which attempts to do some facial tracking of the bottom of your face to inform their 'Personas', it notably still fails quite badly on bearded people where it can't see the bottom half of the face well.
Funny enough the Digital Foundry folks put a Gabe quote about tongue input in their most recent podcast.
https://www.youtube.com/watch?v=c9zfExb5vCU&t=1h32m44s
I'm guessing it's main use case will be VR chat syncing mouths to avatars.
They're probably thinking of it in comparison to the Apple Pro which attempts to do some facial tracking of the bottom of your face to inform their 'Personas', it notably still fails quite badly on bearded people where it can't see the bottom half of the face well.
I gathered as much, but still.