Answer:
Because he could create his own legend about the monkey's paw, since there is no symbolism attached to them in the real world.
In Indian culture there is a symbolism linked to the monkey that is not linked to any other animal. In this culture, the monkey symbolizes the soul. This symbolism was also used by Jacobs to demonstrate that the greatest desires of the soul can be very destructive.
Explanation:
"A monkey's paw" is a short story written by W.W. Jacobs, which tells the story of a family that suffered serious problems after making requests to a monkey's paw with supernatural powers.
That's because the monkey's paw had the ability to place any order, but it would cost an expensive price for it.
Jacobs was probably inspired by Indian monkey-related symbology to write this story. Probably, the paw was the chosen part of the monkey to represent power, because there is no mythology related to the macao's paw, so jacobs was free to create his own story about it.