Extension authors can decide to have their extension on Crowdin and the project is setup automatically and connected to the CVS of the extension.
Coming up with a solution to avoid having duplicates for general fields over and over again for strings like “Title” or “Description” - not only for the core but also for extension authors. Even though the Translation Memory (TMS) is very useful during translation there shouldn’t even be required to have a custom label.
The feature-richness of Crowdin can be used to attract and support new maintainers, e.g. by providing Screenshots of the Backend showing where the translations are actually used.