I don't know its internals, but I assume that your reasoning is correct; it's the same conclusion I came to. But I just wanted to clarify the point about `VGA' to whoever might take that advice. (And it just rebroadcasts what's already on the screen; it just mirrors the console. It does the same thing on MacOS 9 and previous, too.)

BTW, it seemed like the delay was somehow exponentially increased when viewing it over VNC. Actually, even at the console when someone was connected via VNC.