I think the first two pictures are particularly instructive. I’m not so onboard with the rest of them. Here’s why:
Notice how much his upper body is pushed into the corner? Yes, he is down low for aerodynamics, something I wouldn’t advise on the street, but he is shifting the combined center of gravity of the bike/rider combination INTO the turn. That is what allows the bike to lean less.
Pic #4 and Pic #5: I would disagree with the caption on #5. I don’t think height is the key component. I think HEIGHT+LEAN is what’s important. Raising your center of gravity isn’t what allows the bike to become more upright. Using your bodyweight as a ballast into the turn allows the bike’s center of gravity to move into the turn. Think of it almost like trying to add an airborne sidecar on the inside of the turn: that inside weight forces the bike upright in order to maintain the same arc. Thus I think what’s happening is that, as a result of sitting up higher AND being leaned into the turn with his upper body, the rider in Pic #5 has a greater effect because he is using leverage to amplify the effect of his weight shift. The rider in Pic #4 isn’t out of line with the centerline of the bike, meaning that he isn’t using his weight effectively to help his bike around the corner.
Notice how the bike isn’t leaned over very much? It is you say? Ok I admit, with the camber of the road, the offset of the photo, and my monkey pose, it might be difficult to see how much the bike is actually leaning. Just imagine drawing the normal (perpendicular line) to the ground at my tire and you’ll see it’s not a very big lean angle at all. It’s about the same as this:
Anyway, I PERSONALLY think that hanging off is overkill on the street, for two reasons. First, you can get pretty firmly locked into the bike while hanging off, but that’s expecting a clear track, a known road, and otherwise predictable surroundings. On the street, you’ll hit bumps, have to suddenly stop for crazy kids throwing themselves in front of you, etc. Two knees slammed into the tank is always a firmer connection than one knee and a bunch of centripetal force. The other reason is that you occupy more horizontal real estate while hanging off than you would otherwise. This isn’t necessarily a benefit when you have limited lane space and the potential off snagging unexpected obstacles with your outstretched knee.
I absolutely encourage leaning with your upper body, however. The effects are dramatic, and as eon has said, it gives you a more upright bike, a larger tire contact patch, more room to turn if you need it, and ultimately more traction.