When I publish a description translation in the Alpha Wikipedia app, the time until the black "done" screen appears is pretty long.

The user perception of the process can be much more pleasant if the next translation is loaded as soon as possible, and the publishing continues in the background. This is how it's done in the Translate extension: the next string is loaded immediately after the user presses "Publish" so that the user can start translating it. A "saving" indicator is shown in the background, and when the saving is completed, it's changed to "saved".