Casinos offer welcome bonuses for several reasons. They offer free bonuses since they want to be outstanding. Most casino games are similar. Therefore, some casinos use welcome bonuses as a way of differentiating themselves from the rest.
To ward of competition from other Bulgarian sites, these casinos use rewards to entice gamblers. They do this by motivating other players to switch to their casino. When a player joins an online casino, the player registers then receive a welcome bonus. After spending their bonus, they may be hooked to the games offered and end up depositing money.