Using DISPLAYTITLE on user pages can result in misleading information, and should be disabled.
Description
Description
Event Timeline
Comment Actions
The DISPLAYTITLE magic word is provided by MediaWiki core, not the DisplayTitle extension.
Comment Actions
We use display titles extensively on our user pages - to display the real name of the user rather than their username. The rationale for this practice is very context dependent. On some wikis you would definitely NOT want to display the user's real name, but in wikis like ours, displaying the user's real name is extremely important. So, at best, restricting DISPLAYTITLE on user pages should be optional.
Comment Actions
This was not a WMF-level question; it was a MediaWiki one. But @cicalese provided a counterexample (I suppose also non-WMF), which makes me want to take back my request.