The Snap! manual says "The duplicate option makes another sprite with copies of the same scripts, same costumes, etc., as this sprite. The new sprite starts at a randomly chosen position different from the original, so you can see quickly which is which". I perfectly understand the rational (and in Scratch it is exactly the same).
For my teaching strategies (developed in the years by looking at what my students were doing) I use many duplicates of a single sprite, all sharing the same coordinates. As a high percentage of my students is scared by numbers and coordinates, I use them at a minimum. So, to make my explanations simple and their comprehension more straightforward, I have a version of Snap! were the coordinates of a duplicate sprite are exactly the same as the original ones.
To avoid much customization, it would be useful to have a setting to chose between a random or the same position when creating a duplicate.