The most common scenario would be in cooking like this:
In a recipe you need a pint of fluid (i.e. milk, water) but you don´t have some recipient to measure this exact amount, so how do you measure this?
Well after doing some research turns out 1 pint is exactly 2 cups, a cup is one of the most common objects to have at home and luckily you have 1 . So you measure 2 cups and you have your pint for your recipe!