NFC and Wi-Fi Direct for transferring files
These are not alternatives. NFC moves hundreds of bytes and cannot carry a file. Wi-Fi Direct moves files quickly but needs the two devices to find and agree with each other first. The established pattern uses NFC for that agreement and Wi-Fi for the transfer.
Why NFC cannot move a file
Two limits, and either alone would be enough. The channel carries hundreds of kilobits per second at best, and the exchange only exists while two devices are held against each other. Transferring a photograph would mean holding still for a long time, and transferring a video is not worth discussing.
This is not a shortcoming to be engineered away. Short range and modest bandwidth are the same design decision seen from two angles.
The handover pattern
What NFC is genuinely good at is the part Wi-Fi Direct is bad at: deciding which device.
Two phones in a room can see each other and cannot know which one you meant, so they present lists, codes and confirmations. Touching them together removes the question entirely. The tap carries the connection details, and the fast radio carries the payload.
This division of labour has a name in the specifications and a long history in practice: connection handover. The principle applies well beyond phones, and tapping a speaker or a printer to connect it is the same idea.
What survives in practice
Phone to phone file transfer initiated by touching two handsets together is no longer how either mobile platform shares files. The features that worked this way have been withdrawn or superseded.
What survives, and thrives, is handover to accessories. Tapping a speaker, a headset or a printer to configure a connection is common, it works, and it remains the fastest pairing experience available.
So the answer to "can I send a file by tapping two phones" is no on current platforms, and the answer to "is the handover idea dead" is also no.
If you are building something
Do not try to move data over NFC. Use it to carry what the other radio needs: an address, a credential, a session identifier, a short link. A few hundred bytes is enough for all of those, which is precisely why the pattern works.
And design for the tap failing. Anything that only works if the handover succeeds will frustrate users whose phones have NFC disabled, whose antenna is somewhere unexpected, or who are using a case that costs them the read. The tap should be the fast path, not the only path.
Frequently asked questions
Can I send a photo by tapping two phones together?
Not on current versions of either mobile platform. The features that once did this used NFC to start a faster transfer and have since been withdrawn in favour of other sharing mechanisms.
Is Wi-Fi Direct the same as a hotspot?
No. Wi-Fi Direct lets two devices connect to each other without an access point, whereas a hotspot turns one device into an access point. The distinction matters for battery use and for whether the devices keep their existing network connections.
Does tap to pair use Wi-Fi Direct or Bluetooth?
Either, depending on the accessory. The handover carries whatever the target radio needs, and audio devices typically hand over to Bluetooth while printers and displays more often hand over to Wi-Fi.
Why does my phone no longer offer to send files by tapping?
Because the feature was removed. Both platforms moved file sharing to mechanisms that discover devices over Bluetooth and transfer over Wi-Fi, without requiring the two handsets to touch.