I have no idea what your point is here -- is is (very) clearly stated in the COPY help that /W is a one-way synchronization feature (and that SYNC is for 2-way synchronization).
COPY by its very nature frequently deletes files (every time you overwrite). Misuse of a command option is not proof that that option shouldn't exist.
I really doubt that copying a file, in the case of updating it, deletes the older version. If it did, the copied version would be a newly-created file, and have a newer creation time (and I don't think it does). In any event, it is simply my opinion that anything called "COPY" should never cause a file that once existed to no longer exist. I may be mistaken (and I don't care to research it), but I doubt you'll find such a "COPY" feature in any other UI, including MSDOS, CMD, any UNIX shell, and the Windows Explorer.
Yes, it is very clearly stated. Do you suppose that I, or any user, except perhaps yourself, have a total awareness of all the options of all the commands in TCC?
I screwed up and deleted some valuable stuff. And I did so out of a naive, ignorant belief that COPY would not delete anything. So I'm in a bad mood and lashing out at a cruel world. If it's a synchronization feature, it belongs in SYNC. Enough said!