Typically, in the Weblogic days, session cookies were used to hold a server-side session containing the app state. If you just hold auth data in the session this is not a problem. But if hold state like form data in the session it becomes a huge source of errors. Virtually all non-trivial web-based applications had these issues 20 years ago (before „Ajax“). J2EE servers like Weblogic even supported stateful EJBs that brought server-side state to a new (insane) level.

While you could theoretically use JWTs for the same purpose, they are typically only used for authentication. And back then JWT wasn’t a thing.