Not wishing to put words into the author’s mouth but I think the point of this exercise is to cut out a mental step or two when relating what is on the FMA to what the aircraft is going to do next, therefore freeing capacity.
On the 777 there are seven autothrottle modes (eight if you count blank), nine roll modes and ten pitch modes. That’s over
seven hundred possible combinations. Granted, many of those are not likely or even possible but some have complex interactions and the effects of the same are not always immediately obvious, especially on a stormy night approach (or day CAVOK one) after 15hrs in the air. We have plenty of evidence for this...
...also add a limiting time flashing red box...
I think you have to be careful with that colour: it’s generally reserved for “warnings” that things that have gone wrong in a big way and need fixing NOW, like GPWS, fires, windshear, stalls, etc. If I was going to add more, it might be an amber “caution” box, although you already get that when the the airspeed gets too low and having amber when you’re not actually in a caution zone appears to be contrary to the overall design logic.