Earlier quoted context omitted.
Reading NFC transit passes doesn't sound too exciting. I mean, if a phone has an NFC chip, why not use the phone (plus an app) instead of a transit pass, tapping with your phone where you're expected to tap with your pass? This is like your phone wouldn't come with a music player, but would come with a full-fledged oscillograph instead.
There is this Android app that allows you to read your transit pass to check the balance. It's pretty handy with a Clipper Card, for example. http://codebutler.github.io/farebot/ That said Chicago seems to have the most convenient system along the lines of what you're talking about -- you can use plain old tap and pay at the terminal with Apple Pay or Android Pay.
I understand why it would be cool to let your phone replace your transit pass (as it's cool to let your phone replace your credit card), but I don't understand why it's cool to let your phone replace a transit pass reader.