I like writing them when I think there are aspects to why I'd be a good fit for the role that don't get revealed sufficiently by listing skills on a resume or I

I like writing them when I think there are aspects to why I'd be a good fit for the role that don't get revealed sufficiently by listing skills on a resume or I have questions that can save everyone a ton of time. It seems like people do at least read them before interviews most of the time so I think there's some value.