The resume shows experience and the cover letter shows personality. If the job has any kind of soft skills a cover letter is a bonus, if the job is super technical it’s probably not necessary. It also depends on the workplace.

If it is a job you actually want though I would recommend writing something. I’m on a smaller team and read all the resumes of applicants. I actually read them because I’m going to be the one contacting, interviewing, and working with them. I absolutely read the cover letters and give a small bonus to people who include them.