Because it costs next to nothing to digitize and upload old records, online music distribution offers the promise of easy access to the dusty corners of label back catalogues, that were previously only available on long-deleted vinyl.
Unfortunately though, the current batch of online music stores tend to reissue old vinyl in a format that neglects to pass on information like release dates of the original recordings (using those of their most recent CD reissues instead), full lists of those who performed on it, and original liner notes.
All of which may seem like fusty ephemera in the on-demand, pay-per-track world of top-end net labels, but it serves an important role in marking out the history of those old vinyl-based genres, and helping people navigate their way through it… For more information (with specific reference to its impact on jazz) and links to where you can have your say about this glaring oversight by the i-Tunes of this world, check out this article by Wayne Bremser.