Not exactly ground breaking. This is standard functionality of most card readers/encoders. You can do the same with your credit/debit card with the same results. The information on the mag stripe is not encrypted and just plain text.
You're certainly right that there's nothing groundbreaking here; tons of people have done similar things. I just thought it was interesting to clone it onto a random metrocard. However, the data is encrypted, you just don't need to care about the encryption when you're doing a bit-for-bit clone.
