It seems to have been a soft roll out...not actively marketed yet, if ever. I've been able to get it to work but have had a couple issues mainly with screen brightness, etc causing the scanner to not be able to scan the QR code on my phone. I think it's there more as a "convenience" feature in case you forget your pass or for some reason you don't want to take anything but your phone into the park.
I definitely think that an RFID (same tech as MagicBands) system would work better than barcodes and QR codes for everything in terms of reliability and ease of use, though.