Okay here's my take on it as a sys admin.
Archival storage is for data that is not being accessed with any regularity or perhaps not at all unless there is some need to get historical references to something. Many times access to archival data is based upon a request for access (at which time the archive can be pulled and put online) and not on an immediate need.
Some IT departments will keep a portion of their archives online(or at least readily available) based upon the likelyhood of access need, and simply pull obsolete or unused data by request only.
Anyway, for small and medium sized businesses (and even some large businesses), not running HDD arrays can reduce overhead and replacement costs by utilizing other archival mediums (tapes, ODs), when high data availability and high access performance is not imperative.
As far as Sony using a propretary format that only works with there stuff, that's almost a given. But proprietary does not equal fail if there is a genuine market need (or desire) for this type of format.
As always, time and the markets will determine this projects success or failure.