UI
Inter-app audio
Background fetch
P2P (arguably, this isn't a new feature, it's essentially a wrapper to dns_sd)
Airdrop
Significant KitKat changes: *Actual* SMS/MMS API
Storage access framework
Printing framework
Plus, Inter-app audio and Airdrop are essentially wrappers to P2P (which is also a wrapper to dns_sd), so the only real added feature was background fetch. UI
Background fetch
KitKat: SMS/MSS API
Which Android still wins, IMO.
Another benefit I see is that it doesn't actually have the credit/debit numbers printed on the card, so nobody could take a picture of your card and use it to fraudulently purchase things online.
This + Simple would be perfect.