Bonuses always have a terms and conditions for you to qualify, depositing money doesn’t qualify you right away for the bonus because some sites requires you to wage first before you get the bonuses so knowing the TOS is very important.
Since gamblers don't pay much attention to this issue, gambling websites here are trying to take advantage of this by adding new TOS. So it is important to know all the conditions before joining any promotion so that you do not have to face any problem later.
Casino sites aren't obliged to provide a signup bonus there are just sites that do it to attract players. It's their own discretion and a part of their own strategy. If you're the kind of player that sign up just for bonuses, you'll surely have a hard time withdrawing because most of them will require you to deposit a beginning amount to cash out your winnings. They all have their own TOS.
True. This is promoted by the website owners in such a way that the players are not interested in spending time reading TOS when they join the website. So they offer different bonuses for marketing their website, which actually attracts crypto gamblers to that particular website. But since the user does not follow the TOS properly, when he tries to withdraw and does not succeed, he will realize that such marketing offer is more effective for whom.
Most of the people does not read the terms of agreement and even the FaQs so they don't know how the bonuses works but most of the bonuses today are more likely with the use of the more you play the higher the chance of having a bonus such as a rake back thing. For example with the blackjack.fun the highest wager have a bonus btc the same way with another platform. Also, they have the form of surveys and tasks for other gamblers to receive a bonus reward.
When they are not aware of the conditions and for various reasons they are not eligible for the bonus, they blame that platform. But in fact they have to understand that they have to fulfill all the conditions.