We have used Wordpress for years and integrate with 3rd party tools (specifically Bread & Butter IO) to gate content for lead generation and advanced analytics. When memberships was added this was the perfect chance to move to Webflow, but there doesn't appear to be any method to add users to the Webflow database via external authentication.
If we had access to APIs to insert users and create and validate authorized sessions it would allow us to pivot off Wordpress and onto your platform. As it stands now though we can't make the move. I'm certain there are many other Wordpress users that would migrate too if there was official support for external tools that require more granular control over the user database.
+1 for external authentication ... while there is an option to create users via API, this will just "invite" them.