Board Thread:General Discussion/@comment-27609365-20160120215831/@comment-25968376-20160621182327

Without further information from the devs, we can only assume that the distribution of treasures is completely random. That means, with fewer possible crystal-generating treasures available, it's natural that we get fewer when doing the treasure draws (what we think of it is a different story).

However, I really don't think it's useful to spend that much money on something random. If you're in dire need of crystals, it's much better to buy the package deals or use medals to trade since they are relatively cheap now. Crystals are being phased out as a premium currency in favor of MP, medals and the league thing.