Use of Copy and Paste buffer


I am creating a custom, kind of Industry standard keymap for Blender. I am near the finish, however there are still some things I need to figure out.

One of them is use of Copy to buffer and paste to buffer (Ctrl+C and Ctrl+V). I am having a hard time understanding its purpose compared to duplicate (Shift+D and Alt+D). Duplicate seems to be a lot faster and smoother equivalent of the same action.

So I wanted to ask you: When and for what reason would you choose to use Ctrl+C and Ctrl+V instead of Shift+D, and does that situation happen often?

Thanks in advance.

Faster and much more direct to copy from one open file to another without having to use Append is one way. Another is shift D and M are two actions needed when copying from one layer to another. Shift D also puts you in Grab mode which you must commit to right away. So it is another annoying little extra step.