Matt reminds me, "electricity is wave-like too!" -- That's why it sucks, because Tesla was thinking about energy transmission, not signal transmission.
Sure, we could merely use on and off lights, but why not use light frequency for it's beauty and it's precision? DC (really AC because of noise) in computers really sucks and is imprecise too, because we vaguely use +5 volts and up to +3 volts for high and low -- we can't even tell. With light, this high and low is extremely precise, and separable on a very small scale, or a large scale, whatever we want. Way better for finesse. And we don't even have to use moving parts to achieve, as you suggested a camera like shutter system, using exclusively light. Light, travelling at close to the speed of light (it's slower in non-vacuum mediums) is quite fast, and since there's no clock, there's no spatial considerations for synchronicity. I'm so awesome.
