I do a lot of ghostwriting, and am very comfortable with it. However, many writers are not. Keep this in mind, when you’re a ghostwriter: not only does your name never appear on the book, you can’t claim the work as your own, and you lose ALL rights in the work. The work is a “work done for hire”, and all rights devolve to your client on payment in full.
The big benefit is the payment up front, but keep in mind that this payment is all you get from the book.