Cheap Lightning adapter for wired headphones - but why Bluetooth?

It's actually a rhetorical question, because I'm pretty sure I've figured it out.

I bought a cheap Lightning to 3.5 mm stereo adapter for some wired headphones from the dollar store, to have as a spare. It did not even have any brand name that I could find on the adaptor or packaging, other than being made in China.

The packaging did say "Note it needs to connect with bluetooth before use". This puzzled me greatly. 🤔

I started out with Bluetooth disabled via Control Centre. When I hooked just the adapter (no headphones plugged in yet) up to my iPhone SE 2nd Gen it pops up an alert to connect to Beats(x) semi-wired (ie. left is wired to right) earbuds (which I don't even own), and when I tap "Connect" then "Continue" it enables Bluetooth. It now shows up in Settings > Bluetooth as a device with the name "lighting". Note: not "Lightning". Maybe that's because "Lightning" is an Apple proprietary name.

At any rate, when all is set up and I plug the headphones into the adapter, it does make sound come out of the headphones. That's all well and good, but why does it need Bluetooth for a hard-wired connection? I had a plausible theory, so it was time for some Science.

I did an experiment.

1. I plugged the adapter into my iPod touch.
2. I plugged a desktop amp & speaker system into the 3.5 mm jack of the adapter.
3. I enabled Bluetooth on my iPhone.
4. I went to Settings > Bluetooth and found the device "lighting", for which I tapped "Connect", which it did.
5. I start playing music on my iPhone.
6. The music played on the desktop amp & speaker system.

I have another adapter, which is a legit Apple product, and it works without Bluetooth being enabled.

It would appear that all the Lightning plug on the cheap adapter does is supply power to a tiny Bluetooth receiver circuit built into the adaptor.

The cheap version is not actually a "wired" adapter in the usual sense. No data or audio passes through the Lightning plug, and the iPhone is just an outboard battery as far as the cheap adapter is concerned. Well, maybe some data to begin with, because it triggers that pop-up when you plug it into the iPhone. I have no idea why it initially thinks they're specifically Beats(x) headphones, before it switches to the "lighting" device name.

Another thing: When I plug the cheap adapter into my iPod (just for the power) it shows up on my MacBook Pro's list of Bluetooth devices. How may I exploit this, you ask? I can then play music on the MacBook Pro and, by using the iPod to power the adaptor, I can stream the music to desktop speakers or headphones that do not themselves have Bluetooth. Then again, maybe the range is more limited than a purpose-built Bluetooth receiver.

So, I guess the moral of the story is, when shopping for one of these adapters, to check the packaging for any reference to Bluetooth, unless you do not mind going through the extra steps to enable the headphones, or don't care about any additional battery drain caused by enabling Bluetooth.

The Apple branded adapter does not show up as a Bluetooth device.