Since the deployment on French WIkipedia, we have some requests from people who start a translation, publish it, and:
All translations are automatically saved, but it is unclear. The publish button is so big that people beleve it will just save the translation.
Is it possible to add a "save for later" button ?
The current design has automatic saving, which doesn't require active interaction, and publishing creates an article. This sounds similar to T96936, if I understand correctly.
For the foreseeable future we'll probably stick to this design, because the fact is that a lot of users manage to publish articles using it, although it's imaginable that there will be changes in, say, a year. Maybe @Pginer-WMF will have something to add.
It may be also related to T102966: Allow to continue published translations (when they have no additional modifications). That is, people publishing the translation that they want to keep improving it with Content Translation.
There are no plans to add support for this use case on translation view. Publishing allows to switch into personal draft namespace, T102966 added support for continuing translation and T188634 will allow to keep any article for later.
Description says:
All translations are automatically saved, but it is unclear
and that is covered by T106698.
All of the above makes me think that other tickets supersede this request.