The media object is for embedding media within a document (an image, a sound, an animation, some bytecode to execute in a sandbox, or whatever). It's not intend

The media object is for embedding media within a document (an image, a sound, an animation, some bytecode to execute in a sandbox, or whatever). It's not intended to be used as an archive format for storing files (which, as you said, could be trivially accomplished with a byte array for the data, a string for the file name, and some metadata like permissions etc). A file is just one way among many to store media (in this case as an entry in a hierarchical database - the filesystem - keyed by filename). CE is only interested in the media itself, not the database technology. The media object is a way to embed media data directly into a document such that the receiving end will have some idea of how to deal with it (from its media type). It won't have or need a "file name" because it's not intended to be stored in a filesystem, but rather to be used directly by an application. Yes, it could be built up from the primitives, but then you lose the canonical "media" type, and everyone invents their own incompatible compound types (much like what happened with dates in JSON and XML).