Yes, that's correct. That's because to anticipate the existence of frauds that can occur during the bonus lasts. Therefore, if you want to take the bonus, it is better to read the terms and conditions so that you do not violate the rules and can take the bonus. But some bonuses have no terms and conditions and usually, those are from the casino to its members.
Sometimes some casinos' bonuses can be deceptive because getting the bonus can limit you to certain things and there the use can be limited atimes with much limitations. I don't always go for bonus because you winning with the bonus might not count much and there is a limit to how much one can win with it. Since there is always restriction to how much you can win, I don't always go for it. I rather play with my fund and make my winning with the fund I have.
Maybe it leads to a free bets. The welcome bonus usually has no limit, only deposit + bonus = X wagers. And it's like a challenge to play without limits. I prefer to play with promotions like that, If something is free, why do you have to spend money?