I wonder if you are asking where a latch would be used?
Example: It is needed in a frequency counter, to hold a number on the display, while a count is taking place invisibly elsewhere.
A latch is often needed in other meters which have a digital display too.
I don't suppose that is what you are asking about.
At the bottom of this page is a list of threads with similar titles. If you click on one or two, it should lead you to more threads that discuss latch based design.