There's protocol, and then there's implementation.

https://www.quora.com/Why-does-iPhone-not-pair-with-other-no...

I don't have an iPhone, but my cow-orker whose friend has one tells me that it's still the case that you can't transfer files between an iPhone and a non-Apple device over a Bluetooth connection.

I can confirm this, I've never tried before but my wife has an iPhone and I wanted to transfer something from her phone to mine in an area where neither of us had good service. Apple has some "AirDrop" nonsense that uses bluetooth to set up a direct wifi file transfer between iPhones, but to transfer directly to a non-iPhone, you need a third-party app, generally installed on both phones.

I doubt my wife will get another iPhone, especially without a 3.5mm headphone jack.

So what I'm hearing is that the iPhone doesn't really support Bluetooth, but rather a subset.