It was avoiding another ludicrous memorial that got me to take action to change my religion. I swore to myself I would never pass the emblems without partaking again. I was a believer in what Christ did for people, including myself, and felt that it was rejection of him to not partake.
To your original question, I'm pretty sure they just wanted to save the usher some time. It took so long to pass those things around to everyone with usually nobody partaking. What was the point?? Just skip a few rows at a time. On the other hand, getting to touch the plate and glass when I was young was one of the few thrills of being at the KH. Pathetic :/.