Sometimes a company has an internal promotion that they want to make, but they’re required by law to make a national search, post the job for external applicants, or something like that. They post the job, interview some other people, then make the hire they wanted to make anyway. I recently got promoted at work (OK, technically a departmental switch, but I got +25% salary, better working conditions, better co-workers, and transferred the department I’m actually interested in) and they interview a half-a-dozen people, including me, even though they knew from the moment the job opened up that they wanted me. Sometimes bureaucrats have to demonstrate that they’ve looked around and the choice they wanted to make is indeed the best one.
When I was in college I sent a resume out for a temparary co-op job. A week or so later I called the HR manager just to make sure they got it and she made me an offer right there on the phone. No interview or anything. I accepted.