iphonemacostethering
Today I saw an option to Disconnect from iPhone (hotspot) in my list of available Wi-Fi access points, under the status bar icon on my Mac.
I don't remember ever seeing it there before.
What exactly does this command do?
Can't I just turn off Wi-Fi on my Mac, or select a different Wi-Fi access point to disconnect? What problem does this new feature solve?
If you are connecting through the Personal Hotspot on iPhone, it will switch to using the cellular data network that your phone uses.
This is the nature of how the Personal Hotspot feature is designed. See this article on Apple's website.
So in your case, your laptop was not piggybacking through the wifi connection on iPhone. It's an unfortunate design choice but as far as I know a current limitation. Maybe with a jailbroken device you could get past that but doesn't seem worth it for this case at all.
Hold down the option key when you click on the WiFi menu. Then next to the currently active network there will be a "Disconnect from" option. I'm on Yosemite, and so I'm not sure whether this was present on earlier versions of OS X.
Best Answer
This command disconnects your MacBook's Wi-Fi connection from your iPhone's hotspot. Clicking on disconnect will not turn off the Wi-Fi on your MacBook.
If you turn off the Wi-Fi on your MacBook, it will certainly be disconnected from the iPhone's hotspot (or any hotspot/access point for that matter). If you select a different Wi-Fi hotspot/access point, MacBook would still first disconnect from the iPhone's hotspot.
With the recent versions of iOS and macOS, Apple has streamlined the process of accessing Internet on your Mac, via the mobile data of your iPhone. If your iPhone (logged in with the same Apple ID as your Mac) has an active data plan, your Mac automatically shows the option to connect to mobile hotspot, even without you turning it on on your iPhone.
Your Mac also offers to connect to the mobile hotspot on your iPhone if you are not connected to any Wi-Fi access point, and do not have Internet connectivity.
Disconnecting from the iPhone's hotspot will stop the Mac from consuming data via your mobile data plan, and can save you from consuming data unnecessarily and unknowingly (which is generally paid for as consumed) by some apps/processes running on your Mac.