There are three major benefits to planning your arrangements in advance:
Pre-planning ensures that all of your final wishes will be fulfilled. Because death is a difficult subject to discuss, oftentimes your true wishes may not be known or fully understood by your family
Pre-planning can eliminate the financial burden that a funeral might pose on your survivors. And by prepaying, there is a guaranteed funeral price; there's no income tax liability, and your funeral plan is transferable in case you move.
Pre-planning provides you and your family with peace of mind in knowing that everything has been "taken care of" in the manner you specified. It's the best gift you can leave your loved ones.