Earlier on I read on Cosmos blog an article from DZmage which suggests that you should always buy 5 magic dices, and use them roll 6s - even by skipping bosses - so you get the maximum amount of reward. He said he got more bound balens he spent plus extra goodies, so this is a good strategy. After that, I heard complaints from several people who lost the precious bound balens they saved up because they tried this strategy. so I decided I summon statistics and math to verify this.
First of all, I collected a good amount of statistics about Cloud Adventure spins:
A normal dice's average roll is 3.5, while a magic dice's is 6. So with one magic dice, you can save 6/3.5=1.7 normal dice. When you spend 180 bound balens on a magic dice, you get an average bonus worth 123 x 1.7 = 209 bound balens.
So anyway, yes, buying 5 magic dice is a good deal, since you can convert your bound balens into either bound balens or highly useful items of greater value.
But there is something you have to notice: generally, you will get back LESS bound balens than you spent.
If you spend 900 bound balens to get 5 magic dice (and as such, save 8 normal dice), you will get back an average of 24 x (12.57+7.47+6.79) = 644 bound balens only. So if you are low on bound balens, and saving on a gem recipe or some other specific item, you should be careful here.
Here is also another strategy suggestion from me: if possible, try to kill the bosses, if you can reach them via a magic dice roll of 5 or 6. Alternate normal and magic dices, and try to move on as many bosses and chests as possible.
