Good effects makes us less stress but having those bad effects makes us also more stress.Good or bad effects of playing gambling there are some benefits the more important is we cannot be addicted on it to not loose at all.
It is stressful because it includes money, people want to win, they want to earn money, so the stress becomes unavoidable.
People play for money and want easy money and lose in the end which become stressful for them as they lose money Majority of the times and ill effects could be like sleepless night , effecting health and so on. This makes the worst case for them and overall their life become more harder and stressful .