The enantioselectivity of N-dodecanoyl-L-proline-3,5-dimethyl-anilide is also good, but the basic line fluctuates strongly due to containing benzene ring in its molecular structure.
Plus, aldehydes usually have strong smells, and vanillin also contains a ring of six carbon atoms, known as a benzene ring, that tends to make chemicals even smellier.
And scientists already knew how to make it -- one way involved combining methyl alcohol and anthranilic acid, a type of acid with one of those smelly benzene rings.