The reason why casinos have stopped none deposits bonuses is because of abuse from gambler's, I remember when one new casinos that came on board this forum made a grave mistake of giving new accounts without kyc free bonuses and to make things worst for them, they even made the bonuse witdrawable and that was it, the went bankruptcy sue to heavy abuse from bad actor's.
So casino prefer to give deposits bonuses and with heavy wagering requirements to avoid such abuse.
Casinos will always do what is best for them at least they must profit from the process. Despite bonus been a way to foster interaction between a user and the casino it is primarily a way to generate extra income for the casino. With that I am okay but I am not comfortable with how difficult they make their wagering requirement to be. On a normal ground they are indirectly doing exactly the same thing gamblers will do if they continue with the none deposit bonus system. Which is ripping the other party.