Paprika and bell pepper are both members of the Capsicum annuum family, but they have different characteristics. Bell peppers are typically eaten raw or cooked, while paprika is often used as a spice. Bell peppers are usually sweeter than paprika, which has a more pungent taste.
Yes, it will change the overall texture and appearance of your final dish or sauce. But, when it comes to heat and flavor profile, red pepper flakes are the closest to Hungarian or spicy paprika.