I think that having flowers inside the hood of an old car is unusual enough that people would have noticed it without the selective desaturation, so I don't think selective desaturation helped this image convey its meaning. I think that keeping the entire image in color would have make the visuals stronger.
An old motor that someone may decide to bite the bullet and restore it to its former glory, to be honest I'm not very keen on selective desat but I'm sure there are a lot of people here who will appreciate it, good luck