I feel you're kinda talking past ChapulinColorado's comment. He's indicating that for many people they would should have a simple tax filing process where they don't receive money outside of what's reported to the IRS already. Many workers only have a W2 and use the standard deduction. They shouldn't have to pay a 3rd party to get their taxes done, and it shouldn't take them almost any time to file a return.
yes you're also right that people would still need to confirm what their income is (especially if its not reported to the IRS), but that doesn't apply to a large section of the US Population.