Authors should never write as “Work For Hire” because it demeans their aesthetic and demands they are nothing more than ordinary laborers with no investment in the future profitability of the project.
It is hard to persuade new writers away from the “Work For Hire” carrot because the initial, solitary, payment can be more immediately enticing than lower upfront money against a future royalty percentage.
If you get royalties you are in partnership with your publisher. If you are “Work For Hire” you’re used up when you’re done writing.
Publishers live to exploit that hungry author desire for fast money now — and in the process of the “Work For Hire” hiring — the author not only loses a potential profit bonanza, but also sells out their self-respect, self-worth, and fellow authors.