I know that this column can be hide by user's column setting. But, these methods are not good, because user can show this column again.
'user name' is used when login If the 'user name' is leaked, it's a serious security problem.
In any other window (function), only 'Full name' of User is showed. (Ex. Folder table, Information page, search result, New Change Task, etc...) But, 'User picker' Window show not only 'Full name' but also 'Name'.