A lot of times, nobody reads these white papers, but there is a huge credibility boost from having them. It says that there's something substantive here. "Sounds like good stuff."

I have seen a lot of companies do this and it's terrible. You get SEO mostly from long form in depth articles and dumping it into a PDF will tank something that would be page 1 to page 5. Google will prefer a well setup blog over a file download ten times out of ten. Unless your whitepaper is a unicorn the search results will go to someone else

From personal experience Some bosses I've had preferred to share them when selecting providers