Yes, it is completely useless and doesn't work properly. It's only there because of Garmins marketing: we have more features than others. (and garmin really doesn't care if they work properly, or at all)
You cannot turn it off, but it doesn't cost battery anyway. It's based on stepcounts (which are measured anyway) and changes in altitude, measured by the barometer (which is also always on)
To be honest, the "annoying" alert that tells you to "move" is the only one really interesting. Sitting still for to long is not healthy.
10.000 steps doesn't say anything. You have to move with a raised heartrate to get a health benefit. But the stepcounter you can simple ingnore, and you can turn of the 10.000 steps reached notification.
Floors count doesn't work. And beside that, if you want to move more sure you take the stairs. You don't need confirmation from your watch. But, again, number of floors can easily be ignored.
But the move warning is important. Annoying? Yes! That's good. Make sure you move enough so you don't get the "annoying" alert.
