Steve demoed it during one of the Macworld keynotes, so I don't think it's too much of a stretch to think it was put there so he could demo the effect. I recall him minimizing a playing Quicktime window to show that the compositing window manager was drawing the video in the 'genied' window.
Does anyone know if there is a way to disable this without turning off the genie effect altogether? Essentially just remove the slow motion aspect.
Likewise, hold Shift and click the minimized window icon in the dock for the reverse.