Here’s my use case: I’ve got a MacBook Pro hooked up to a 27-inch Cinema Display. I have the external display set up front-and-center on my desk, with the MBP off to one side.
The location of the MBP makes it inconvenient to use as a second display. I’ve tried moving the displays to different locations and no matter what I do—too much head-swiveling.
So this week I decided to hook up my 10" 6th Gen iPad as a sidecar display, park it below the big Cinema display, and I kinda like it. I can just drop my eyes and see what’s on the iPad. Mostly it’s just empty, but it’s great if I just have a little something I want to refer to. For example, I needed to update a directory entry for my employer’s HR software–I put the instructions on the iPad and did the work on the big display.
My wife needed copies of about a dozen receipts–I moved the list to the iPad and compiled them on the big display.
Not a lot of use, but very handy when I do use it.
I also anticipate moving Slack and IM windows down there when I have an ongoing conversation.