I don’t even understand exactly what this is. Apparently, you connect it to a phone compatible with NFC, which is a wireless type of connection.
Being 25.7 mm (2.57 cm), it is not really a CD.
Until we know more about this format, maybe set Other?
Is that heading into “Digital Media”? Bit like when you have music on a USB flash drive?
I wonderif the “disc” actually contains the music data or if just has a download code/link. For the former case, I could see an argument for this being a separate format or packaging type.
It’s obviously not a CD as defined by MusicBrainz. Looks a lot like another proprietary variant of [STYLE-2047] new format: KiT Album - MetaBrainz JIRA.
I’d use Other.