I am aware of that, but many of us just don't want PDFs to ever open in our web browsers, even if we don't intend to download them for saving purposes (they do get downloaded for viewing no matter what).
I far prefer for PDF files to open in my chosen PDF viewer, as they're easier to review there. The few extra seconds taken to fire it up when I hit a PDF link is more than worth it for me.
Brian - Windows 10 Pro, 64-Bit, Version 1809, Build 17763
Here is a test to find out whether your mission in life is complete. If you’re alive, it isn’t.
~ Lauren Bacall