A casino welcomes new gamblers often using bonuses and promotional offers especially when they sign up for the first time.Meanwhile That's a huge working strategy thats designed t attract and keep gamblers attracted to using the same feature all the time.
Welcome bonuses don't keep customers; they're meant to attract customers and make them taste the casino. It's their experience in the casino that will determine if they will continue playing there or if they will use another one, since welcome bonuses are mostly given just once after the first deposit. I don't consider it as something that can keep players to continue gambling there.