For an emotional emphasis.
E.g. in a story by Philip K. Dick one of the characters refers to our planet as 'she' ('look how beautiful she is...' or smth like that). It's obvious that he's carried away by the sight - but is it appropriate to use 'she' when describing let's say Venus, if I want to emphasize that the planet is like a living being. Wouldn't it be em.. campy, so to speak, if I used it in an article but with an emotional emphasis.
It's a common literary device to refer to inanimate objects as "she." Some otherwise normal men speak lovingly of their cars as "she."
However, choose carefully. Most of the planets are named for male gods, so there might be some discord between "she" as a planet when "he" was a god. Venus, obviously, works in the female.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.