As Siyron said, rules are rules. There is no point. It's a pure luck system. If you are lucky, you get rich, if not, not. It's a very brutal RNG system, with very few very big winners and the mass gains nothing, so there are indeed a lot better systems with a much wider spreading of winners, but well... Squares decision. Ask them, why they implemented something like that. Got nothing to do with the original GS and it's also kind of strange for a MMO. Maybe it's for their homeland audience. Gambling is a big thing in Japan, though very restricted by law.