Abuse of any system is inevitable and as long as money is involved humans will always make attempts to abuse and take advantage of the system to they own advantage, so the casino is aware of this possibility of abuse of their bonuse system and that is why they make some tough rules that make it almost impossible to get away with that stolen funds from the casino.
Most of the bonuse that are offered by most casino comes with high wagering requirements that make the gamblers to spend all the money back on the casino, so for sure we have to come to a point we're we can only get what we want from those casinos when playing with our own deposited funds.
Deposit bonus is one of the most interesting things for new users and it will be their challenge to complete all the rules they apply in the deposit bonus. Sometimes it is impossible to conquer it but still there are those who manage to do it well.
I never take a deposit bonus on every new site I register, because my type of game is directly in a big bet so if you win with a deposit bonus on a big bet and we have to complete some of the rules, it will be quite frustrating and take time so that the final result is the balance will be zero because of chasing the target to complete the task to be able to claim victory in the deposit bonus.