Eliminating drag. Because the head uses air pressure to keep itself off the platter, that air is also going to be pressing against the drive, causing friction, and requiring the motor to work a bit harder. By parking away from the platter altogether, you're eliminating that source of drag and friction. Regarding the orange widget, the damage happens over hundreds of thousands of park and unpark cycles -- a little wobble and a little rubbing after each one, which will eventually be enough to get things out of alignment and thus, broken.

The difference between near the rim and near the spindle is that air pressure. If it's near the spindle, it still has that drag that's making the motor work harder. Near the rim, that pressure is gone.