For what it's worth, some input from Aikido's cousin here.
In Hakkoryu, suwari waza is used only as a way of teaching by isolating the upper body, much for the reasons Philip described on page one. There is little lower body (knee) movement involved until the aggressor has already lost their balance or has otherwise been overcome.
In this way it's by design that a pupil should work hard at the application of a technique from seiza, because there are important lessons that may be overlooked when the lower body comes into play with the same techniques while standing. The goal with suwari waza, though it can be frustrating, is to make a pupil work harder to understand and really grasp some of the intricacies without relying on the lower body and footwork.
Phi, we even have the office chair waza covered! It's called in short, "kiza dori". See the images 32/34.You can't tell because of the hakama, but the poor fellow is sitting in a plush, expensive office chair while being assaulted. Sorry, you don't get to see what happens to the bully in these photos, but he will never steal a donut again.