Probably because of the "Sonic" fast food chain, which was probably an in-joke at the time. But that's a wonderfully awesome find. I've heard about this, but never knew there were actual video footage of it.
On a more related note, I remember Sega had quite a few Sonic features on their web site (95-97 ish) on Sonic (Sonic History for example). One feature that I still remember was about a game called Twisted Mattle. It was going to be published by Sega, but made from another developer starring Princess Sally. It was a PC game that was going to have a predominately female cast (Sally, Bunnie, and a few original cast members like a skunk girl with Native American clothes), as well as Sonic, Tails, Antoine, etc. I even had a couple of tech demos on my old PC (a town demo with Sonic stuck in ball form that you manipulated like a debug code; Sally in a desert level compete with haze effects), but alas that was a good 11 or so years ago and the HD had met with a virus. I'm having a heck of a time trying to even get info that that the game even existed now; as anything about it is pretty much gone. But I'm not surprised that Sega were trying to make a SatAM tie-in game. Heck, a few characters show up in Sonic Spinball. And if you look for Sonic X-treme info, some of the scenarios STI came up with even featured SatAM characters. This game would have definitely departed from the series roots, but it could have turned out neat like Tails Adventure or Chaotix (baring the lackluster good ending).