We have a galaxy S2 (T-Mobile) and a few Galaxy S4 (AT&T) in the house. Have never used the NFC but was curious if it uses any "mobile data"? I don't have much data and it's hard to search on here for this because it NFC is too short of a word to search for. So, if my mobile data is disabled, will it still work? Also, is it faster than Bluetooth and what are the advantages? Thanks!