You don't have to declare it because it is considered a hobby.
In the USA and other countries gambling winnings are treated the same as income and gambling companies are required by law to withhold federal income taxes.
If I had to pay taxes I would quit gambling. The risk wouldn't be worth it.
Does your country tax gambling winnings and if so do you declare it yourself or does the gambling operator withhold the taxes on your behalf?
It varies I guess.
If the casinos will tell you that you've won a tax-free lottery jackpot then you won't doubt them as it comes from them. And any gain that someone makes whether it's from any hustle or gambling, I think they're all taxable and will be considered as income to an individual.
Again, this varies per country and really depends on how laws in your country's have been made. So, in Australia, check it out in which state are you so let's put that out and try to check the other areas if gambling gains are taxable there or not.