if we use the wrong pronouns, the sentences or paragraphs would be confusing, and will be very hard to interpret. it will also make a person struggle very hard to be able to analyze the information in the correct way, or the way it is intended to be
The reader will get confused during reading. If you are talking about a girl named Jessica buts use the pronoun him in your writing the reader will try and read back to see if they missed somthing about a boy. Another reason is it can make the writing seem sloppy and UNFUN to read. but as well since where students It's because we'll get a big old F XD.