For Nuance and Maniphest, at a minimum, we want grey users to be able to login and interact with Phabricator over the course of a session, not just a single page. Other types of interactions, like Legalpad verifications, might be better captured with single-page worklfows, but if someone reports an issue on Twitter to Nuance, they should be able to login and interact with that ticket over the course of multiple pages.