As a colorblind user I'm not quite sure what color the send+mic button is, but I'm drawn to it much more strongly than the normal send button. At the very least you'd think they would have had a pop-up confirmation message...
It doesn't seem like Google tested this on many real-world users before deploying...?
Then again, I don't watch TV so maybe I missed out on it being used.
Furthermore, the icon doesn't have anything for you to read, since it uses an image (whose meaning may still not be clear to an older or disabled person; it kind of looks like an ice cream cone to me).
A UI that requires the user to read every button and look at every icon that they click on because it may have been changed to do something completely different is a terrible UI.
While I might notice a new color, I'm not certain that I would.
In doing usability design even for astronauts or pilots I don't think you could fully trust a user to behave as you describe.