The Science Fiction and Fantasy Writers Association recently released an article about tired disability tropes. It’s a great resource for those who want to include disabled characters in their stories.
Why write about disabled characters? For for the same reason you would include any other character, because disabled people are a part of the world. Their experiences, their stories, and their representation matters.
However, there are many times people write about a disabled character who has a gift so powerful that their disability is functionally erased and they might as well not even be disabled at all.
Read the SFWA article here for more information.