Gambling is addicting because it is a way for you to earn money without any skills required. Unlike other methods of earning money, you need to have qualification and knowledge, gambling dont. However, they dont want to know that gambling also make you lose instead of win.
That is a complete misunderstanding about gambling. Gambling shouldn't be called as an earning money method because they are made to give us just an entertainment and to keep things more exciting kept an option open for gamblers to win big money if they are lucky. But if gambler tries to chase the win then they may lose a lot of money in gambling instead making money.
I agree winning and earning is two different thing. But I believe that gambling is one way for other to earn money by winning games in poker and blackjack.
Anyway, gambling being entertaining and the added benefit of winning a stake just add to the excitement that make our brain produce more hormones that later on is one factor that the person became addicted to the game.