I bought a MFRC RC522 rfid module for my Arduino Leonardo, after I purchased it I notice it only supports ISO/IEC 14443 Type A, and not Type B. I was curious what applications uses Type B anyways? I checked wikipedia, but I am still uncertain about it.
ISO14443-A and ISO14443-B are used for the same things. Modern ISO14443 NFC tags are even compatible on the APDU level because A and B both use the ISO7816-4 command-set.
The main difference between the two technologies from the usage point of view is, that for historic reasons the B style ISO14443 is used in the frankophone regions of the world while the A style ISO14443 is used in the rest of the world.
They have been competing standards build and lobbied into use by two competing companies. Then ISO came around and tried to unify them under ISO14443-4.
From a technical point of view they differ on the physical layer, e.g. they use a different modulation and anti-collision low-level protocol. The capabilities or what you can do with the technology, how fast you can transfer data and so on is almost identical though.