Why the page beside the summary changes the read
A reviewer's job on a summarised document is attribution, not re-reading. In two windows that becomes tab-switching, and tab-switching is exactly what lets a wrong page reference survive a review: the reader checks that the sentence sounds plausible against a document they only half remember.
Here the summary sits beside the page it cites, and every quoted passage carries the page number it was found on. Clicking one moves the document instead of asking you to scroll and hope.