Currently Server-Translations only loads translations files in datapacks, the issue with this is that other mods that are not only server side won't have their translations files loaded.
The datapack system should be kept but a asset should run in parallel when mods which run on both client and server sides are present.

Issues that can't be fixed with Server-Translations until this is closed:
Fabric<->Discord-Link#136

afaict translations are no longer loaded from assets in 1.4.16.

Is that intentional?

This was never fixed.