It's very hard to grasp the conceptual understanding of WHEN to apply monotonic queue.

It's hard to identify/figure out if a monotonic-queue would be useful for a given problem, as it doesn't seem to be covered in any textbook.

I looked into Cormen book and some others.

Why is it that it's not in textbook or taught in university courses as a data-struct?
Can anyone point to text/academic literature where the concept and when/where to apply monnotonic queue is explained?