Fame
Ghostwriting is common in medical writing. That is, you write an article or report, but it won't have your name on it. This means if your document is successful—the obesity drug gets approved for production or the medical report on dyslexia gets a lot of buzz—you don't get the credit. The fame and glory belong to the drug researchers and the medical professionals who did the research or patient observations.
Other medical writers may work for blogs or magazines, and their names are typically included on their work. But again, medical writers aren't the ones doing the actual science—they're just making it more interesting for the rest of us. No matter how concisely you describe that groundbreaking report, the Nobel Prize is still going to go to the person with the bad haircut who did the research in the first place.