I've read about this as a plausible method for high-speed, long distance space travel. The main drawback, if I recall correctly, is that if any kind of space debris or micrometeoroid hits your sail, you're screwed. And the odds of that are slim but increase over a long trip.
yeah, that first one is definitely CGI but they did a good job matching it to the moving camera.
the "old film" look on the second one looks like it was added after the fact.