Bluetooth is really slow, that's the main drawback.
WiFi Direct is a really great technology but unfortunately it is as simple as its name implies: it's a peer-to-peer version of WiFi. It establishes a connection between two devices, but you need to do everything else (like figuring out how to send files over the socket) yourself.
There are plenty of cross-platform apps that implement WiFi Direct file sharing though.
What I find weird is how easy to use is (was?) Wi-Fi Direct between Android phones and how this isn't a common thing in Windows or other non-mobile OSs.
I have just Discovered Windows 10 have Wi-Fi Direct if you have both Wi-Fi and Bluetooth adapters, and it's as easy as enabling it and right clicking a file to share it. It's a shame this isn't common knowledge nowadays
WiFi Direct is a really great technology but unfortunately it is as simple as its name implies: it's a peer-to-peer version of WiFi. It establishes a connection between two devices, but you need to do everything else (like figuring out how to send files over the socket) yourself.
There are plenty of cross-platform apps that implement WiFi Direct file sharing though.