Lights are used indoors all day long in much of the world. If you don't like poking holes in your roof, then you probably don't like sun windows either.
The gravity light requires manual labor to produce light, has moving parts that are more likely to fail, is more costly, and produces less light.
The gravity light produces a shamefully small amount of power - about 100 mW ("one deciwatt") by the manufacturer's own measurement. Even given the increased efficiency of LEDs, the illumination provided by one of these "bottle lights" is still about 100x greater, it's basically free, and it doesn't require you to tend to it every 15 - 30 minutes.
The gravity light requires manual labor to produce light, has moving parts that are more likely to fail, is more costly, and produces less light.