Only for MFI-licensed accessories, or for everyone?

I think there's been fast pairing for MFI devices for a while now. I very vaguely remember an Airplay-enabled stereo once invoking some popup on my iPhone to please share my Wi-Fi password with it (presumably over Bluetooth, or maybe Wi-Fi direct?), which I found really neat. This was over 5 years ago.

Other than that one stereo, I've never seen that flow anywhere else, and I've probably spent hours of my life entering my Wi-Fi passphrase using a d-pad text interface.