Why I couldn't tell you, but have been frustrated each time I make changes or move the units that have those double row versions especially, but often it's partly the location of my avr, too. I have since opted for banana plugs as at one point I was swapping things in and out a lot and couldn't take it no more. I've seen 'em spread out in a long single line, like my Onkyo, which is a bit easier than the double row ones. RCA type amp preouts are even easier (don't have to install the banana plug to the wire) but my older amps don't have the banana plug option on their binding posts, tho and probably not all avrs do either.
"I realize that somebody playing free music isn't as commercial as a hamburger stand. But is it because you can eat a hamburger and hold it in your hand and you can't do that with music? Is it too free to control?" - Don Van Vliet (aka Captain Beefheart) discussing commercial success in the music biz