Gambling bonus shouldn't be the main or sole reason a gambler will bet or play. It could be a reward for buffer the moment they slowly ran out of funds to spend, but should not be the entire reason why they are playing in the first place because there might be a chance they'll just play the moment they feel like they will receive some bonus or if they have a bonus fund at hand. Quality of games and the service itself of the casino should be their driving force to play so that they will bet and play over and over. Because if their main reason to gamble is the given bonus, then if it will be eliminated, the players will suddenly stop as well.
While it is good to give promotions and rewards that the players will benefit, it should be assessed first whether it will be efficient in the long run and sustainable.
Gambling bonuses are about money and we often advise that we should never gamble for the money or profit because there are so many lives who already been destroyed in regard to this. Still, I don't think it was the fault of the gambling sites. Usually, gambling bonus requires us to deposit our own money and play more.
If you ran out of money, you will never complete their requirements so there are no bonuses for you. There are rakebacks which you can claim but I think this mostly unlocks once we reach the first level of the site's VIP program. The amounts are still tiny and won't help that much if your goal is to recover your previous losses.