Some EBAs might be huge and contain many bundles. Right now whenever a bundle in a EBA is updated, the entire EBA is re-assembled and re-deployed to the server. That of course, can be expensive if the application is big. So it would be nice if only the updated bundle was re-deployed to the server.
This feature will probably require changes to the server's deployer code or might need a new set of API for deploying & managing bundles within or outside of EBAs.