I was just pointing out the alternative because I personally think that it's inefficient to rely on manual clicking, and I happen to have lots of room in my setup to handle additional keybinds.
As for your single keybind approach, I did some tests and found that the following seems to work:
/micon "Hide"
/merror off
/ac Hide
/statusoff Hidden
I personally didn't encounter any problems during testing to remove Hidden, even after waiting for the 20 second recast on Hide to reset. See what works on your end. I'll probably stick with using separate keybinds just because I know that's always reliable.
I absolutely agree that a single button toggle of Hidden should just be baseline design, however.
Edit: The merror line doesn't even seem to be necessary, but you can keep it in if you like.