Your PC can save you time and money and increase the accuracy of your return. The best answer is because it's easy and it's accurate. When you use your computer for tax preparation, you don't need to know the law nor do you have to spend endless time trying to find the right forms. Computer-assisted tax preparation saves you time. It has been estimated that the average time of 7.5 hours to manually prepare a return typically is cut in half with electronic processing.
Corrections are easy.
You can redo a whole return in seconds rather than hours. Tax preparation programs are accurate and, in many cases, guaranteed. Most professional programs will pay any interest or penalties if an error was because of poor calculations or inaccurate programming. The fewer the errors, the less likely you are to be visited by an inquisitive IRS agent. Computer-prepared returns can save you money.