If you don't have any media on it, and you don't intend on using it for storage, then just ignore it. MDs don't NEED to have a hard disk in them, so I would conclude that it is not necessary, apart from for storage (and as you say, 20 GB isn't going to get you very far).
The snapshots are like a bang-up-to-date DVD installation disk i.e. everything you need. Just follow the DVD installation instructions.