It’s not like Apple is the only vendor who accepts hi-res source files either.
Apple decided to make a PR campaign out of this. An on top of it, you have to be certified to be part of their “exclusive” club.
Be wary of the marketing and feel-good paragraphes inside the MFiT paper.
CD Baby made a summary on the most important requiremens.
Although iTunes doesn't reject masters for specific numbers of clips, audible clipping
caused by excessive levels to the encoder may be reason for tracks to not be badged
and marketed as "Mastered for iTunes."
Apple is basically rewarding good masters with a shiny badge.
( ͡° ͜ʖ ͡°)
I can’t say why the MFiT barcodes are sometimes shared with other platforms. Maybe they all got the same files.
On the other hand CD Baby asks for a unique barcode for MFiT. Not sure if that is required by Apple.
yindesu already hit the spot. Different barcode usually means different tracklist and/or attachments:
Here is an example release. It has a booklet and video on iTunes and Amazon. While GPlay, Spotify, Deezer, Qobuz do not. Non-booklet-non-video release share the same barcode: 4260395982121. iTunes and Amazon: ¯\_(ツ)_/¯
Interestingly Amazon has it flagged as AutoRip but the CD doesn’t contain a video and has less audio tracks.
I need to find a digital release without videos but with booklet.
Some other articles I found interesting while browsing: