These processes is a good one to understand but who gives the site 100 satoshi, wouldn't the site completed some task to earn such satoshi? Let me understand how the site gets their 100 sat.

Actually, it's true that nothing in crypto community is free, even airdrop as said as free is faulty, back then in 2017 when only submitting ETH address without tasks gives you free token. Ethereum blue was the free coin someone got that time.