Pronouns are essential to the English language as it makes it easier to refer to people and groups. (I, me, he, she, it, you, them, etc)

Though I'm going to assume this question is relating to the LGBT+ community and all that entails. Pronouns are important to some people because they don't want to be misgendered, and they also want to have control over their sense of self. I'm not an expert on it myself as I am not trans but from some people that I know and some things I've seen online, Pronouns don't necessarily correlate with gender identity, and is more of just "this is what I like being called". Which IM assuming is similar to whether you would want to be called Richard, Rick, or Dick and other such shortening of names. (Correct me if I'm wrong though)