Helpful shortcut, I make quite a few at least
We should only add this item if the viewer can create a project (or should disable it if they can not).
From within a controller you can normally call $this->hasApplicationCapability(...) to test the viewer for a capability like this, but that isn't available from within an Application object. You can do this instead:
$can_create = PhabricatorPolicyFilter::hasCapability( $viewer, $this, ProjectCreateProjectsCapability::CAPABILITY);