From afar, the Opera: pages on it.ws are very close to the pages with the template {{Éditions}} on fr.ws or the template {{Versions}} on en.ws (and similar system elsewhere).

The main difference is having a separate namespace A second major difference is that the templates on fr.ws and en.ws are very light while the {{Opera}} template took data from Wikidata (but that's an independent problem, it's possible to change the {{Éditions}} or {{Versions}} templates to do exactly the same thing without having a specific namespace).

I'm almost convinced too, but in order to create a new namespace on a project you have to convinced the local community. That's why I'm still playing the Devil's advocate role and want to learn about the inconvenients of this system