The chips are sub-cents per unit in terms of cost and weigh milligrams. RFID chips come in many flavours the ones most used are passive, i.e. basically just a bunch of wires printed on a tiny piece of carrier material. The label on a shirt contains more resources by weight.

Really only wires, or is there still a (tiny) chip on there somewhere?

While it can indeed be helpful as an indication, cost often doesn't factor in externalities such as pollution during production, and recycling after use. Paper has much fewer problems in those areas.

100% agreed, but if you truly want to go down that route, you'll quickly find that basically NOTHING has externalities priced in. If you truly were to do that (which I'm personally not opposed to), prices of pretty much all goods and services would need to be adjusted.

It's ok, these will go right next to the trillions of cigarette buds thrown in nature each year and probably the trillion of trillion microplastics and nanoplastics shed each year.

Nothing to see here and there can't be any possible negative consequences when people are making so much money.