In simplest terms: SOB was/is a classical album; where a symphonic orchestra was replaced by a monophonic Moog synthesizer and an excrutiating/exquisite recording process - using an 8-track tape recorder. Yes: you could argue that the instrument and process used were 'novel' - but SOB was a classical album by design - that was the fundamental goal of the project.Strictly speaking (and by definition), I'd argue it was a novelty - it was new and unique.
The accolades/awards it's received by both the public and the music industry (Billboard 200/RIAA/Grammy) support this fact.
In greater context: SOB help to provide the 'proof of concept' needed to fuel investment into the R&D required to realize technical advancements in both synthesis and mt recording - we are where we are now partly due to the success of SOB.