May be a dumb question but I’m not sure what this does or if it’s really necessary. The manual doesn’t give any explanation of it other than saying that to shut down the unit, press shutdown from the home screen then turn it off using the power switch in the back.
What happens if you just power it off at the switch without first going Home>Shutdown? Will I create a singularity? 
Or is there a real risk of bricking the unit or something like that?
Hello.
This shutdown function was added latest firmware to let the CQ finish all its internal task before switching off.
This is useful when you have a recording session, letting enough time and being sure that all is correctly written in the SD card.
So it’s basically just to finalize an active recording session and if I’m not recording I can just turn it off with the power switch without any harm?
Yes, I do it very often with no pb.
To echo Frenchie’s answer but from A&H directly - you can absolutely just turn your CQ off without doing the shutdown process with no ill effect. The shutdown is just there to finalise any read-write processes to USB/SD. So, if you’re not recording, you can just switch off.
Why not use the shutdown button ? Are you in a hurry ?
I have seen comment from A&H that apparantly no problem to just use the power switch. I wonder what the story will be, in case of a corrupt SD card (just example).
Like all digital consoles, they are basically software , running on a piece of hardware. A shutdown process seems like a good idea to me, to close/stop all the processes the way they should, before switching off power
Yes, sometimes in a hurry, sometimes just forget. It’s another couple of extra menu dives just to turn the thing off.
From reading previous posts it looks like the shutdown button wasn’t even there in the earlier firmware versions so it doesn’t seem like it would cause damage to not use it, other than maybe a lost recording.
The function not being present in earlier versions does not mean it does not have to be used. Maybe they added the feature to prevent damage to the unit, but it looks like it only stops recording sessions.
Oh, well … I’ll probably use it as much as I can.
In a previous post MarkF from Allen & Heath explained that not using the Shutdown button will not cause any harm or damage to the unit.
“…from A&H directly - you can absolutely just turn your CQ off without doing the shutdown process with no ill effect. The shutdown is just there to finalise any read-write processes to USB/SD. So, if you’re not recording, you can just switch off.”
That said, I’m sure I’ll use it more often than not and the only time I may forget is if we have to do a quick teardown, usually only in cases when there’s another band scheduled to start right after us.