You told me some things that you can do in the Terminal Tab, nothing about what you can't do. Many people are going to think "oh, a terminal, I can ssh into my computer at home and retrieve some files." I don't believe you can do that with the Terminal Tab. Perhaps calling it a "Terminal" is too general. I'm just asking all these questions because there isn't any docs that I could find on it.
So a description of the Terminal Tab might be:
The Terminal Tab is where you get messages and feedback from the hardware you are connected to. It will echo the gcode being sent to the device. Some commands can be sent specific to the hardware. It doesn't have any connection outside of the specific hardware OctoPrint is currently connected to.
Is that concise enough? Would you make any changes to that description?
The somewhat harsh tone of @PythonAteMyPerl here aside (btw, I'm German, for me that only classifies as "somewhat harsh"), he's got a point.
It's impossible, especially with the available resources, to explain everything in the detail that you, @Tone, so far hinted at expecting, and just taking things for a test drive does indeed clarify tons of things, or at least it appears to have done exactly that for heaps of people in the past.
Now... I don't want to have play moderator here and nuke an otherwise IMHO so far productive discussion on what's lacking with regards to documentation, so let's just agree to play nice and keep the frustrated outbursts at bay on all sides and instead see what can be improved without turning to spoon feeding every single thing (because in my experience that indeed only teaches users to become more and more dependent on someone holding their hand, and that is something this and every project that isn't backed by hundreds of support staffers simply can't handle).