I seem not to properly understand what stakes are and how they are calculated in bounty campaigns for ICOs. Why don't they just for example state they'll issue 20 tokens of a particular coin instead of stakes. Good examples I've come across are;

•   From 26 to 99 friends - 15 stakes
•   From 100 to 249 friends - 30 stakes
•   From 250 to 999 friends - 65 stakes
•   From 1000 to 9999 friends & followers - 130 stakes
•   10000 friends & followers and more - 300 stakes

-Hero/Legendary: 3.5 Stakes
-Sr. Member: 3 Stakes
-Full Member : 2.5 stakes
-Member: 1 Stake
-Jr. Member: 0.5 Stake

How are the stakes converted into tokens? Forgive my ignorance.