When we built the first version of RenderStreet, we started with the idea that we can take advantage of Blender’s pack external data feature and make sure the files are uploaded properly, with all the data needed to render them.
As they say, no plan survives the contact with the customer, so a while after we launched we ran into issues with Blender features not supported by the pack operation. Some of them, like the external libraries, were fixed by the dev team. Others, like the font embedding, had workarounds. But it became obvious that sooner or later we will run into something that can’t be supported at all.