This composition reminded me of a painting on the nursery wall when I was young. I deliberately centred the main subject and further emphasised it with a shallow depth of field by using a wide aperture. It is a photographic nod to 'Naiive Art'
So many disdain vignetting, considering it as a limitation of FF sensors and wide lenses/f-stops.
There are times when it could be unwanted but there are just as many when it is desirable; such as in this picture.