It's not Bad , what happens is that the majority of players get involved with the bonuses, because a bonus can Compromise your Deposit and it turns out that in order to withdraw if you are not Satisfied with the casino game , you can't do so Until you meet those Betting Requirements , when you do them you can hardly get your Money back, this is something that Happens to many , I don't use it personally, I avoid them at all costs , I like to play only with my money to avoid bad Times.
I agree with you that the bonus system is not bad, even though we have nothing to lose by taking the bonus, but we may achieve something with the bonus or by the bonus, though there is a high chance of being a winner and making the required wager to achieve the required number of bonuses. If there is no such risk, then it would not be considered as gambling.