Bad effects will only happen if a person will get addicted to gambling and will forget that gambling will do no good if abused. Do gambling only in a spare time and with a spare money to avoid bigger losses.
Abusing it will cause harmful effects and as given if you don't gamble with due understanding and diligence, you can be in the worst situation that you can't even get out.
It's hard to make gambling as a source of income but others are doing it and believing on it, works for others but for majority it won't.