Some systems have very large LDAP systems and may not want to have the LDAP sync parse through all of them on a regular basis. Additionally they may not want to wait for the timed LDAP Sync and would prefer to push users on demand.
This would be used by a system like IDM, to provision users when they become entitled to access to the system.
Secondarily an API that allows for additional provisioning, other than users. (NetFolders, Sharing of folders, etc) that would apply to users. The SOAP API left behind in Vibe was almost enough to do it but you turned this off in the Filr build.