To me, it signals "If you are likely too impatient to read through the entirety of a science-heavy article, here is a rough summary. However, be warned that this is a compromise and doesn't capture the whole essence of the article." Whereas summary means "Here is everything you need to know, in short."

As an impatient reader I wouldn't have even noticed "summary for impatient readers" if not for this comment. It's a couple of paragraphs in and disguised as sentence text.

A nice big bold Summary heading works wonders!