What are the different types of flours used in making Rava Idly, Dosa, Halwa, Ladoo and Upma in Indian Cuisine?
What are the differences between Wheat flour, Semolina flour and Rice flour in cooking these dishes?
This may help you make some decisions about what flours to use/keep on hand.
But in general, the difference between flours relates mostly to whether your looking for elasticity (gluten content) vs crispness (rice flour). For semolina, there is obviously very different ways to cook it such as in puddings or creamy dishes but it can also be dusted on things as a breading to make it crunchy.