I believe the offset is there to make sure that the duplicate does not cover the original.
When users Duplicate something, and nothing appears to happen, they may thinking that the function does not work.
With the offset, there is no room for confusion. You see the duplicate immediately.
(I'm with you though. 99.999% of the time, I need my duplicates in the exact spot as the original.)
3.6 GHz 8-Core Intel Core i9
64 GB 2667 MHz DDR4
Radeon Pro Vega 48 8 GB
Software OS 10.15.3