One reason Discogs distinguish releases is because they have different prices on the market.
For example, a vinyl having 50 copies pressed in Japan back to 1983 may have a very different price than the exact same one repressed from same master with the exact same cover art in US in 1990… don’t ask me why, but this is the reality.
For major albums, like The Dark Side of the Moon CD it exists thousands of “releases” (different factories, different presses, different cover arts, different labels/catno/barcodes). Distinguishing them is a real pain, often differences are very slight. Whether they are different “releases” from MusicBrainz users point of view if often a very subjective matter. After all, digital music should be all the same … but in practice, we have different discids, different colours, different texts, etc… the limit is very fuzzy sometimes.
The case of vinyls of different colours is a good example, they may be made in the same exact factory, or not, and sometimes the cover art colour also differs, are they different “releases” or not ? But everyone agrees 1973 japanese vinyl release is pretty different from 2010 german vinyl release, even if they have exact same content and cover art, they will not have the same price on the market. Nor 20 red copies have the same price on the market than 200 black copies, pressed in the same factory, released at the same time.
MusicBrainz users aren’t only Picard users, they may be as well collectors, librarians, researchers, hobbyists, musicians, label managers, etc… if you merge all releases in one, because you think they are the same based on your own criterias, you may exclude users that don’t have the same criterias.
@chirlu said something correct, it is hard to manage all those releases, but my opinion is it is even harder to manage if you merge all major albums releases in one, because differentiating them is already hard. Many users are already uploading cover art totally unrelated to the release in MB (vinyl cover art for a CD release for example), and it is a mess to manage.
@aerozol is right, too much data isn’t much an issue in our database, i prefer “under-merged” releases than “over-merged” releases today because we don’t have tools to easily manage, for example, cover art merged by error.
@chaban seems to think Picard users are confused by those, but in fact most just don’t care about releases at all, and just use the first one, and i would think it is up to apps using MusicBrainz to please their users. Do you truncate a Wikipedia article because it doesn’t fit in your screen ?
@HibiscusKazeneko : in doubt, just create a new release, merging it later is always possible, and you can easily duplicate an existing release. Unmerging isn’t that easy.
Something that happened to me already, finding the exact release matching barcode/catno/label/year/country and full cover art, but noticed the tracklist was different, different discids, almost same matrix runouts… prolly an error in early production, quickly fixed, but in this case … same release or not ? We all agree different tracklists = different releases right ?
We have the case of the same “release” of a CD pressed in different countries/factories but released at the same date, with no distinction of CD source (from example CD pressed in Italy sold in France, while in the same time the CD pressed in France was sold in Italy, official CDs, same release date, exact same cover art, different matrix runouts, same discids). In this case i tend to think it should be considered as the same release with different matrix runouts. This is often the case for big sellers albums in Europe, when one factory cannot handle all.
So, in general, i don’t care matrix runouts, but for major albums with tons of releases i’m very picky about them because it is very hard to distinguish releases, since differences are very slight.
And to be sure one upload the right cover art, it is much better to have details in annotation, in clearly separated releases, etc… people are already messing between cassette and vinyl cover art … even though differences are obvious.
If you merge all The Dark Side of the Moon CDs in one release, because, after all, that’s almost the same data, and almost the same cover art (in many cases), it will not be easy to manage where it stops, we’ll then merge vinyls/CDs/digital and then you’ll end with Atom Heat Mother cover art for it … and collectors will hate you
To conclude i tend to think the smallest difference is still a difference, whether this difference is important is very subjective.
For me, my 1983 first edition CD bought from the artist during the last concert of the band is very different from the 2016 nth edition sold on Amazon having the exact same music / cover art / barcode / label / catno. Clearly different “releases” for me