He'd <u>not</u> be able to translate his own life experience into a theme because a clerihew is a biographical poem about some famous person. You need to translate that person's life experience into a theme.
He'd <u>not</u> learn the fine art of writing poems because a clerihew contains lines of irregular length and metre.
Short as it is, a clerihew contains rhyming words; thus, a student might benefit from writing clerihews by gettting some experience working with rhyme.