  The rewards a blockchain miner earns vary with time. Most of the time is
spent mining without receiving any rewards, and only occasionally the miner
wins a block and earns a reward. Mining pools smoothen the stochastic flow of
rewards, and in the ideal case, provide a steady flow of rewards over time.
Smooth block rewards allow miners to choose an optimal mining power growth
strategy that will result in a higher reward yield for a given investment. We
quantify the economic advantage for a given miner of having smooth rewards, and
use this to define a maximum percentage of rewards that a miner should be
willing to pay for the mining pool services.
