Can the new android dynamic feature modules
potentially be used for releasing an update of some dex files / features in production without forcing the user to upgrade the application through the playstore?
No, this can't be used for this purpose.
However we (Google) are working on an In-App Update API so you can trigger an update of your app from within your app, so the user doesn't have to leave your app to get the newer version. See https://youtu.be/QdoEcfibG-s?t=1762