Why not re-read the article and let me know who you think will be able to purchase the information gained from voicemails that have been transcribed.
Then tell me what kind of safeguards there are (none) when your CPA, lawyer, doctor, bank officer, or other 'trusted relationship' (let's call it as it is, anyone) leaves a message for you for that message NOT to get into the wrong hands.
Who's doing the transcribing, and who will buy this information?
Furthermore, I'd bet that even if the person calling does NOT use Google Voice, that person's information (caller ID) will be captured by the software, that number will be "black paged" (reverse-lookup) and information gathered from the transcription about the calling party will be sold as well.
Who is going to safeguard that information?