I absolutely disagree with this.
If you are able to have savings after all living necessities, you can be using not more than 1% of your income on gambling. No need to think about the budgeting like it is something special.
I spend more on things that add up to me than things that do not add up.
After all types of spending 1% of the rest might be too low for majority of the people. If anyone can warn 1000$ in a month and spend 500$ as monthly expenses then 1% will be only 5$. Don't you think it is too low budgeting for gambling. I think anyone can bet any amount which the person can afford if loses.