Yes, and sprite rips from the classic Sonic games make sense when we're trying to reproduce the classic Sonic games in 3D. Even then, notice that the sprite rips we DO use are very specifically the type of things it doesn't matter if end up always facing the player. So yeah, the monitor and emerald sprites are taken from classic Sonic, but that makes sense.
Most people on the forums aren't doing that with their sprite rips. They take a 2D platformer sprite and try to turn it into a character WAD. That does not work at all. The scale is always wrong and the frames don't fit into our character WAD system. If we had made our Sonic sprite by using the sprites from Sonic 3 for Sonic, it would look awful. That's what these guys are doing.