Just for reference, the cloth is included with the standard glass XDR but in the instructions they tell you can use similar products, but the cloth is recommended. Yes only the Nano textured absolutely require and you can’t use any liquids with it.
“Apple sheeple will buy anything as long as it has an Apple logo on it.”
Perhaps this is true in this case
But seriously though, it was a good publicity thing I guess. And since they are already making them for the Pro Display XDR, why not make some extra $$ and sell them on the side? Now let’s see them do this for more accessories - the colorful iMac mouse and keyboards comes to mind. Black Apple stickers, anyone?