Is the problem that users are clicking a link to your Discourse site from Memberful and not being automatically logged in, or is the problem with users who are visiting the Discourse site directly and are unsure about how to login to Discourse?
The first problem could be solved on the Memberful end if they used this structure for links they create to Discourse: Create a DiscourseConnect login link. I don’t have a Memberful account, so I’m unsure what gets displayed on their end.
I’m not sure what could be done to improve the second scenario. The way it’s expected to work seems straightforward to me. Clicking the “Log In” link on Discourse should automatically log any users who are logged into your Memberful site to Discourse. If the user who clicks the button isn’t logged into Memberful, they should be taken through the Memberful login flow, then automatically redirected back to Discourse. It would be good to know if this isn’t working as expected, or if it is, but users are still having trouble figuring out how to log in.