What you write is that: intellectual property.
Like other intellectual property, it has value. And, when you die, you want the things of value you own to go to people you chosen.
That's why a smart writer should visit Neil Gaiman's Web site and read his take on intellectual property and wills.
Who is Neil Gaiman and why should he worry about intellectual property?
"Bestselling author Neil Gaiman has long been one of the top writers in modern comics, as well as writing books for readers of all ages. He is listed in the Dictionary of Literary Biography as one of the top ten living post-modern writers, and is a prolific creator of works of prose, poetry, film, journalism, comics, song lyrics, and drama."
As with other references and pointers on the Internet Writing Workshop Blog, the administrators, individually and collectively, assume no responsibility for the accuracy or honesty of the information. Writing is a tough business. Caveat emptor.