Pipes, localhost, who is counting, as far as I'm concerned that's the same thing, making it seem as if for the purpose of this test that's a significant difference is simply conversational trickery.
If you have tested this on real live servers then there is no evidence of that in your posting, and to suggest that this:
http://dpaste.de/32o8/
is anything but a localhost test is simply bogus.
The only use case where you may be right that poll is advantageous as far as I can see is streaming media servers (video, audio, other large files), image servers are the ones with the worst active-to-total ratios, especially if the images are small. I should know, I only serve up a few billion of them every day. A few years ago or so I was stupid enough to think that video was hard, man was I ever wrong. Repeated connections to the same host, that's a much bigger killer than pumping bits.