Would you really trust the IRS to do your taxes????
They ALREADY are doing your taxes.
They compare everything in their computers to your Return.
They know what you owe before you do.
Your Return is only useful, at all, for some very limited situations.
You may have added a Child, gotten Married, gotten Divorced, or had very high Deductions (using the Standard Deduction will become even common for Tax Year 2018).
Of course if you have a Business your Return will not be simple.
But for your average Employee, the entire process is simply a GOTCHA.