Since gamble site kindda risky, you can invest on your own for example if you have shop to handle, you can use it to expand your shop globally so you may have alternate currency. And if you have more, you can spend for help advertising your shop !
Yeah your right that gamble is risky and your right better to start to invest it in your business so that you can make more income..
For me blogging is the best because you are just starting a small amount to invest it in your blog pay for seo pay for promoting and earn in few weeks or months..