when i make a stew such as the above, i'll saute' onions, garlic, peppers etc. then i'll add the spice(s), but cook them over low heat. frying paprika too much/too high heat will make it bitter. i'll cook it over low heat for a few minutes.
i do it because i've been told to do it that way. i don't know if it makes much difference whether i lightly saute' it, or just dump it in once the liquid is in there. gently frying it is supposed to bring out the oils, more flavour?