As a ghostwriter, we not only don't get publicity, but many have no editorial rights. That depends on the contract.
During my early years, I wrote manuscripts and after the celebrity okayed everything, I mailed them to the publisher. No one consulted me about any editing. I wasn't always pleased when I saw some of the changes, but there was nothing I could do.
Another downside is that a few authors demand endless rewrites. One famous leader insisted I sit in his office with him and his secretary. He read every sentence aloud—which took hours, while I followed on my laptop. The two of them discussed every sentence and decided whether to keep, delete, or change it.
On the spot, I made the changes they wanted. A month later, we went through a second oral reading. And finally a third. He was demanding in other ways, but that was the worst.
Despite such downsides, I've enjoyed a lucrative career as a ghostwriter. And I believe God has given me the temperament to work with others who want their stories or ideas written.