Nowadays a lot of websites are written in a style that goes on and on and on dancing around a topic, adding historical context all in a terrible writing style only to lengthen the text for SEO. In such cases a summary can be a good thing.

It's really not that deep. There's writing you read for its aesthetic merits and writing you read for its contents. When you want the latter but the piece is written for the former a summary fixes the mismatch.