The "Crawl and scan by the shortest route" for Manual Crawl Import is a function to reduce the number of transitions to the final page of the imported crawl results by changing the access order of pages, thereby reducing the scanning time.
For example, if the page access order during manual crawling is "A→B→C," the scanner will access page "A→C" and if page C is accessible, the scanner will scan page "A→C. (It will not crawl or scan page B.)