I think you are completely misunderstanding who they are targeted at.
GREE are making much more money out of new whales than the older players who have spent years of play stockpiling masses of all sorts of orange and purple goodies (except those few that are needed in large quantities for every hero and have no easy and convenient supply (fad diets for example)).
To the older players the purple, orange and gold chests are all overpriced and worthless as the chances of giving something we actually need versus something we already have 1000's of is slim to none.
However for a new player, starting at the bottom and trying to rapidly climb to the top, they are a veritable gold mine of delivering exactly what you need to promote your Heroes and progress in contests to boot. If you're a new player, with financial resources to spare, orange and purple chests (as well as gold) are superb.