If you can click twenty times a day, every day, at the end of two months you will have 0.000024
The base reward of free roll is not 2 sat for all users. Depending on your wagering amount and number of lottery tickets you have purchased so far, the base reward can be up to 40 sat.
I think you haven't noticed the message above the prize table.
"
Play MULTIPLY BTC, BET ON EVENTS or buy lottery tickets to increase your FREE BTC rewards by up to +0.00000038 BTC"