Build speed incentive to cleaning up `export *`?

As part of modularizing an existing codebase, we’re using export * in module map module declarations, as sources currently heavily underspecify their first-order #includes and so rely on transitive inclusion to build successfully. Aside from code cleanliness, does anyone know if there are any other incentives to removing uses of export * and making sure all sources properly #include their first order dependencies? (e.g. would this translate to a build speed improvement, as fewer unneeded modules are pulled into scope).