Hi n80,
Thank you for your question. This was spurred by listening to a friend's setup in a comparable-sized room, using an old Sansui integrated and Polk 5s. What stood out is how good it sounded at low volumes. The sound stage was smaller, but almost better because of it. Everything sounded more integrated, like music should be. It's a bit like that old notion of where you want to be sitting in the concert hall, up close so that each instrument is distinct in space, or further back where everything is blended into a harmonious whole. In the end, the setup was perfect for the room. To answer your question, I think it's in large part about fitting the system to the room, but perhaps there are other benefits of a lower-power system: smaller # of parts, higher-quality of said parts for same price, leading perhaps to better resolution at the volume they were designed to be played at, or, a narrower soundstage that may sound better in a smaller room. I don't really know. Now my friend's system in particular was not more resolving than mine, but I think my point is that his stereo is almost perfectly adapted to its environment. The interesting thing is that the market for low-power system is really bimodal: either low-cost products meant for the casual consumer or astronomical speciality combinations of efficient speakers and low-power amps.