I make one of these shakes for breakfast almost every morning. Sometimes I make extra for a quick snack mid-morning too. The intent of this is something filling, but healthy.
Sometimes I will sometimes mix in 1t of some kind of protein powder (e.g., whey powder) if I need the extra filling nature of protein. Be mindful of how much protein powder is added as it can make the shake very filling -- I used to to 1T but that was far too much.
As a note, I used to mix with a hand blender wand. I found that did not give the smoothie the same fluffiness, but it was passable.