Pilgrims would have sought the place out. Locals set up stalls to sell souvenirs and trinkets, food and drink, and someone decides that they are getting a marble slab made (in Hebrew no less!) to say that it was “right here” that the miracle occurred, and he sets it beside his kabob tent.
That makes sense. Relics and pilgrimage sites were (and still are ... the Via Dolorosa in Jerusalem is like a continuous strip plaza of small shops) big business.
Buy your religious action figures here! (batteries not included)