If something doesn't add anything to your life, you shouldn't be spending money with that at all. However, you have to be careful if you consider gambling as an essential expense. Just because there is a chance you win money from it, it doesn't mean you are going to win. Keep in mind the chances are against you on long term, so the more you gamble, more money you are likely to lose. If you think that way, gambling also doesn't add anything to your life, right?

But then, there is also the entertainment aspect. You may think gambling is more entertaining than to spend money on other things, so there is the possibility it adds something to your life on that sense. As long as you adopt the right stance and mindset towards gambling, it will be ok.