Re: The point of aikido osae
The point of the pins is really based on what you see as the point to the art as a whole. IMO the pins are just an extension of the same things you work on in every other aspect of the art. Basically, it's just a different situation to apply those same things.
Without laboring over the details, relax, take the slack out of your body, take the slack out of their body, connect to them and control them. Being seated makes some things easier and some things harder.