Let’s say you scan a piece of paper and convert it to a PDF. Did you know your PDF can have its text and images processed to make it easy to search through? This also makes it easy for other applications like SharePoint, BOX, Dropbox, and others to index your content, so you can search for them in those applications.
Depending on which PDF engine you use, you might run into issues. Some PDF engines just take an image and create a PDF wrapper around it. Then, your file repositories can’t index it because it’s just a glorified picture of a page.