Preview is one of those essential things that sets macOS apart from the other operating systems, and contributes to that “Mac has good UX” vibe. Last time I opened the Windows equivalent, it tried to sell me on Microsoft’s PDF-alike format… and asked me to connect Office365. Another tiny macOS feature I love is that you can drop a file icon on any Open or Save dialog to select the file in the dialog. On other OSs, th…
I can't stand when I have to deal with a PDF on Windows on my office computer where I have the free copy of Acrobat. You can right click on a page and it's got "rotate" buttons up at the top. But when you click on one, it takes a second to think about it and then opens a popup to offer you a free 7-day trial of the Pro version. Rotating a page is too powerful a feature for Adobe to not try and sell it to you. https:/…
In fact pretty much the only time I open a PDF in preview is to merge 1 or more PDFs (show the thumbnails, copy and paste them from one to the other).
Otherwise I never use Preview for PDFs and I reference tons of PDF based specs.
On the other hand I use Preview to quickly crop or markup screenshots all the time.