Some personal names become famous for a conspicuous trait. “Ḥātim,” for example, may evoke generosity. Calling another generous person “Ḥātim” presents that person as belonging, by rhetorical claim, to the kind of exceptionally generous people.
The proper name is being interpreted as a class-name; the metaphor can therefore be treated as original. Simply mentioning a historical person does not produce such a metaphor.
Contrast: “Ḥātim arrived” can be literal when it refers to the named person. “This host is a Ḥātim” can be figurative when used to magnify generosity.