It might behoove you to actually read the Apple document. It states, "Some fabrics, like leather and denim, might cause permanent discoloration that will not wash off." It doesn't say, "Don't do it." It simply states that doing so may present the possibility of discoloring the card in some situations. This doesn't mean it WILL happen, especially in most situations. It's just so they can say they told you so if anything adverse ever happens to your card from wear and tear. The wording here isn't much different from how any other company writes care instructions for their products.
I have zero use for the physical card as I’ve got others that are always going to pay higher rewards. Since the card is apparently a delicate little snowflake, I’m going to have mine matted and framed behind glass, and I’ll hang it on the wall where I can gaze at it and admire it all day long without ever having to worry about it being damaged.
