I have done this twice on two different content types, and it caused a degree of alarm...
The new displays on the back-end show warnings that no template exists (screenshot), in this case for Pages.
1. Investigating, I clicked on the 'create content template' button, which of course creates a content template and assigns it to Pages.
2. I decided I didn't want to do this, so closed the content template without putting anything in it (lol), and went on to do other things in the back-end.
3. The effect, of course, was that all the pages on the site disappeared, because they were all using a content template with nothing in it.
Not a problem for me at the moment (just makes me feel like an idiot), but if someone less familiar with Types does the same, perhaps even accidentally, it could have a serious impact, especially on a live site.
I think it would be a REALLY good idea to give a warning along the lines of 'Are you sure you want to assign this template to all <Pages>?'
Very good catch. While we first thought it was a good idea to create snd assign a Content Template when clicking on that button, we will definitely review this in the next iteration of the feature.
Thanks. FYI I've just done it accidentally again (in the last minute - and this time on a live site), but this time from the front-end toolbar. I was looking at the 'design with toolset' item, and accidentally clicked on 'create a new template for this page' - at least that only switches off one page!
This ticket is now closed. If you're a WPML client and need related help, please open a new support ticket.