What would be the income source of that site?
The pocket of the owner
A human that is likely bill gates to have that platform, and make it as a charity gambling casino
.
No, they are just targeting something else but you people are focusing on generous world. But this world is not like and it is more cruel than you could imagine. Many gambling houses are offering some small money on regular basis to kick-start your gambling. But the sole purpose is making you familiar with gambling environment and in other case, you will slowly find it interesting so that you will start depositing your own hard earned money. Who knows ? You may get addicted even with free money based gambling itself and then you will stick with gambling. This is what their pure expectation for providing free coins/spins.
on the said section, I may be able to find one but still I cant have my winning withdrawable its just like I played poker on facebook and nothing but just my time was wasted.
Not just with free coins. Even you will be depositing your own money, you may not find chances to withdraw because this is how gambling will deceive you. Yes, you may not stop your gambling until your total bankroll disappears.