It seems like Facebook built this so they can feed the data from people using their api to train their eventual messenger AI/assistant.

They were actually acquired by Facebook some time ago.

I don't know why you are being downvoted, but this reminds me that thing about facebook/google/etc. that if there is no product you are the product. It also came to my mind that they may be after your users data for their own models..

They "may be"? As far as I heard, Google is pretty clear about using spoken language input for their voice recognition API for precisely this purpose.