On wikipedia I use Yurivict.
When I try to login to phabricator, wikipedia password doesn't work.
"Login or Register" button on the "Login or Register with LDAP" screen doesn't lead to "Register" function at all, only to "Login".
Login screen on https://www.mediawiki.org/ says there is no Yurivict account, but when I try to create the Yurivict account there, it fails and says there the similar account.
So I had to bail out and create this Yuri271 acct to even be able to create this PR. All these problems defeat the purpose of "Sinogle login".
Also you IMO don't need to tell users LDAP login, this only introduces another concept (LDAP) in addition to MediaWiki, WikiMedia, WikiPedia.
Now this leaves me confused, and unable to use single login at all.