I've been curious about this same problem but I want to convert to Pixar USD since OBJ and FBX are basically 20-30 year old formats and not actually that efficient.
I've been investigating using Blender to batch import LDD files and batch export to USD. This project is being updated and is based on an older GPL Blender LDD import script/plugin.
https://github.com/cuddlyogre/ExportLdraw
Unsure if I want to bevel or convert the geometry to Sub-Ds.