It doesn't provide everything that flash does, and IIRC only supports flash animations. Some things that flash provides that JavaScript (at least JS provided by the server) can't provide: Webcam and microphone access (think sites like ustream and stickam), exact font control (there was a demo site a while back that showed the same site rendered on different browsers to demonstrate how much even the placement of fonts differed), etc.
I'm no proponent of Flash, but to say that Gordon can completely replace Flash is not the truth.
I'm no proponent of Flash, but to say that Gordon can completely replace Flash is not the truth.