If you see the Las Vegas stage show that this is the soundtrack for (as I have) you'll understand that Gnik Nus actually becomes a textural musical bed that sets the tone and feeling for "Something," an aerial ballet.
While anyone with a computer can play any music file backwards, this was a carefully considered choice and fits perfectly into the show that it was created for.
I've heard that "Moonlight Sonata" story, but if you actually listen to the first three notes of that piece, backwards they sound more like the beginning vocals from "Because"...specifically the syllables "'cause the world"...check it out...
Actually, if you read the liner notes (at least on the regular edition, not sure about the DVD-A version), it says that Giles Martin (George Martin's son), who was helping his father with the song selections, had actually messed up and accidentally reversed "Sun King." They were trying to make it flow into "Something", but they didn't mean to completely reverse it. It was a typo, and they ran with it. But I think it was a nice touch.
Yeah, a lot of people have said that "Gink Nus" was lame and I don't understand where the heck they're coming from. I think it's great and it touches on what The Beatles' made famous anyways, playing things in reverse!