Income tax is collected each time you are paid through payroll. You will never need to remit your own taxes. (Freelancers paid as contractors via IRS form 1099-MISC income, must hold back their own income taxes as well as the employer portion, then pay the IRS and state each quarter.)
Your W-2 earnings statement makes it easy to file your annual income tax return.
Home loans, car loans, apartment rentals and other forms of personal credit are all easier to obtain as a W-2 employee because creditors typically treat pay receipts and the W-2 earning statement as a more reliable validation of your personal income.
No saving for quarterly and annual income tax, the way freelancers paid by form 1099-MISC income must do.