Firstly, online casinos make money on welcome bonuses by attracting new players. These bonuses act as incentives to attract new players and maintain the existing ones. So, the more players the casino attracts, the more money it is likely to make.
Also, welcome bonuses encourage players to start playing as soon as they join the platform. The amount that the casino offers are usually small compared to what they will make when the players play their games and place wagers. Welcome bonuses also help online casinos stand out from their competition, which promotes more signups and more money in the long run.