I thought that's exactly the point of Scientific Reports: to publish "reports" (i.e., not proper "papers") without caring about their impact or importance, as l

I thought that's exactly the point of Scientific Reports: to publish "reports" (i.e., not proper "papers") without caring about their impact or importance, as long as the science (however little of it there is) is done properly. i.e., you literally send them stuff that isn't good enough to be published in a proper journal. It's meant to be a dreg journal with low reputation; it's a feature, not a bug. The idea is to allow people to publish their work (e.g. to finish their PhD), but everyone knows that further investigation is needed before stuff should be called a proper finding. I think of it as the "workshop" version of a journal.