Very interesting and extremely impressive! I tried using the voice chat in their app previously and was disappointed. The big UX problem was that it didn't try to understand when I had finished speaking. English is a second language and I paused a bit too long thinking of a word and it just started responding to my obviously half spoken sentence. Trying again it just became stressful as I had to rush my words out to…
I'm a native speaker and this was my experience as well. I had better luck manually sending the message with the "push to hold" button.