For me, winning isn't just about withdrawing your money from an online casino it's also about having control over the money you use for gambling and over yourself. Sometimes, you might be able to withdraw your winnings, but if you end up depositing it back into another online casino because you lack control, you're not truly winning (Based on my own experience). That's why I believe you're real winner when you can control your gambling habits.
Always keep yourself under control especially your emotions and greed while gambling. The next step is money management when you win something good from gambling it will attract you to gamble more and if you continue to gamble like that with the whole fund you will lose it all again at one point. For this reason the strategy I use is that I withdraw my winnings and gamble more later using my original gambling funds. Although I use gambling for fun, this means that management protects me from many losses
Management of money is an important education and knowledge gamblers need to master inorder to put into sufficient use, their gambling winnings.
I think this is why some governments decide to tax gamblers that win, so that they learn how to manage their winnings from gambling instead of on frivolous spending.
When gamblers learn money management, the society becomes more developed and am sure there won't be any negative talks from close persons bothering on the misery a certain gambler is facing due to excess spending and poverty lifestyle despite winning big at least sometimes from gambling.
I don't know how the government collects tax from gambling winnings. As far as I know the government always levies tax on gross annual income. Gambling winnings cannot be called passive income so I don't think the government will take any kind of tax from a gambler until he cashes out his balance. But if somewhere the government takes tax from gambling winnings then it is a good initiative to make gamblers more aware and every gambler will be responsible for these rules. But till now I don't know where such law is reflected. Because gambling is still illegal in my country.