I guess they needed to fill a candidate quota since they ended up hiring internally. In that case it was a giant waste of my time. It was a panel interview. The HR manager was nice but the others seemed uninterested or indifferent from the start. They didn't tell me when I should hear back from them so I checked in myself after a while. I also guess once you have applied for a dept and you didn't get the job, you won't get any other interviews for other roles within that department.