Actually, it was in fact used back in the early days of Conquer 1.0, because there was no GameSetup.ini before around 41XX
It was dropped because the password, email, security question, etc were also stored in a folder at that registry location.
Here's some screenshots of what the 4017 client added (before I lost the download, anyway. Also, changed password and such of course.)
Edit: Also, idk about the logs folder. Never had anything in it. But the accounts seemed to be named after the UniqueID