I agree that one shouldn't discount an idea just because it's currently technically difficult. But right now, getting coral larvae is not very practical.
Sea monkeys produce cysts which can live for a very long time in a dry environment. These are harvested conveniently right here in the United States, like at the Great Salt Lake in Utah. What's even more convenient is that the cysts wash up on shore by the gazillions, and can be collected with front-end loaders.
Coral reproduction isn't that simple. Even if you could ship the planktonic larvae, what encourages them to settle is largely unclear. In the end, you would end up with teensy colonies that may settle in a part of the tank you can't see, and will take months to look like anything.
Aside from the challenge, what do you see as the benefit?