Added in STYLE-361. Download card is the most common word for this. The phrase "includes music card" gives no relevant hits on google, but "includes download card" gives thousands.

I would also recommend putting it under digital media, as unlike other formats, this does not contain anything other than a redeemable code for digital media. As it is right now, this format is highly hard to find due to the uncommon name and placement. It's very unlikely that any editor would find it if they do not consult the wiki list of formats, as evidenced by the small number of releases for a very common format.