I don't get a card or setup my smart phone for NFC.
That wouldn't be the primary use for the key card. It's a terrific back-up to get into and start your car. Can be given to a trusted person to let them get into the car temporarily, can be disabled if needed, etc...I don't get a card or setup my smart phone for NFC.
You can use both on some trims.
I don't find it convenient to take a card or smart phone out and place it against the door handle to unlock.
Easier for me to just grab the handle with my hand to unlock while the smart key is in my pocket.
Some people may like the NFC if they never put the smart phone away and always have it in thier hand.