lens – What are the technical reasons for designing lenses with irregularly shaped openings?

Some lenses have odd-shaped openings, such as a star or shuriken. This seems to be intentional since making rounded or polygonal "normal" openings is quite simple (as I observed when disassembling the iris of several lenses). What are the technical reasons for making such openings?

I remember reading somewhere a comment that corrects some defects of the lens but that I could not confirm.

I am do not ask questions about the openings formed by the photographer for an artistic effect.