I mean if you want to deny the sky is blue when plenty of experience says otherwise that’s on you.
I agree that it would be very inefficient to send voice recordings, and those would be easy to pick out with some packet sniffing.
But a locally processed txt file of keywords would be such a small amount of encrypted data that it would easily pass under the nose of any security researcher and they would have no idea unless it was decrypted.
So no, this is not debunked.
It’s $3 which is well worth the time saved by not having to design it from scratch.
Someone had to use their skills to create it, do you think they should work for free?