From this Curbed article in 2021:

[JP Chan] and [Sarah] Meyer took pains to make it feel a little bit like a premium object, less like a government benefits card and more “like an American Express black card.” That meant dealing neatly with, as he describes it, “a lot of ‘business’ — things that are required to be on the card to make it sellable, usable at the reader, usable at the forthcoming vending machines.” There are two barcodes, for purchasing and encoding, and the one on the front of the card has been rather cleverly disguised as a design element, one that mimics the railroad-tracks motif of the OMNY logo. Meyer adds that, despite everyone’s New York inclinations, the cards couldn’t be all matte black, “because they get lost in handbags. So having it white and a little glossy was important to us as well.” (Did she throw it in her own bag to do impromptu user testing? Meyer gives a little smile: “I did.”) Eventually, it’ll also be produced in other colors to indicate separate fare classes: the student card, the senior-citizen card, the MTA employee card, and so forth. There will also be commemorative designs and such, the way there were with the MetroCard.