Comment by anigbrowl

A simple example would be how the prices displayed in stores aren't inclusive of tax. So if you're grocery shopping, you've got to keep recalculating the tax as you go to know your total in advance. For anyone on a tight budget, that sales tax impacts their buying decisions and mistakes could be costly. Property or income tax liability can also involve a lot of effort to calculate correctly.

If you're never had to worry about this, congratulations! But for many others its an extra level of stress and complexity that they'd prefer to minimize.