It feels awkward at first, but it really helps with a smartphone. You get used to it. I now use speech-to-text for the majority of the text input I perform on my mobile, including text messages, short emails, and search.

I also do everything I can to avoid the need for a lot of text input on mobile and save it for when I have a real keyboard. I agree with other users that the decline of physical keyboards on mobiles has had a terrible impact on their real-world productive use, but speech-to-text helps alleviate that a little bit at least, if you don't mind homonyms getting mixed in there occasionally.

The one thing I'd really like to make voice control less awkward and faster is a push-to-talk button instead of the stupid activation phrases.

I want to just pull my phone out of my pocket, hold a button (or ideally hold a button on a smartwatch) and speak a command. Using the button release to finalise would also speed things up, because the phone doesn't have to wait for silence to know you're finished. It would also work better as a keyboard replacement. Select text box, hold button and speak to type.

It just seems so obvious to me that I don't know why no one's done it yet.

Sure, but it really, really depends on the user. People with accents seem to have a hard time getting it to produce usable results. I only have anecdotes, but they seem to suggest that foreigners and first-generation English speakers have a hard time getting accuracy out of speech-to-text.

My only concern with voice commands is the tracking and search recording that inevitably takes place when using something like Google Now, Siri or Cortana.

If I don't use regular Google search due to privacy and tracking concerns, why would I use Google Now?