The cords are not designed to be under constant tension. In a regular alpine ski boot, you have a rigid plastic cuff wrapping your entire calf which prevents you from tipping over backwards if your weight ever gets off your toes (which happens all the time). In a mountaineering boot, you don't have that high cuff and you will have nothing stopping you from tipping backwards. Your bindings will pre-release and you will immediately fall out of your bindings. The cords prevent that.

I have skied in the cords plenty on my approach ski setup. They're a life saver, especially in variable terrain and when skiing with a pack.

Any boot you ski in, take it out for a test ski first... maybe 3-4 miles minimum. You do this to find where you're developing blister hotspots because I guarantee you will. Manage them before you go out for a real climb.