The "simulated sheet of paper" aspect of PDF's make them a pain on anything with a screen size smaller than needed to show the whole "pdf page" at a readable size to the user at once. On anything smaller one has to zoom and pan around.
However, you can see for yourself. Assuming you have a smartphone/tablet, just install a PDF reader if it does not already have one [1], then start viewing various PDF's.
> Personally I’d prefer viewing a responsive and accessible HTML version instead of having to pan and zoom the original pdf.
I agree.
[1] here is one you can install if your device does not already have a pdf reader: https://f-droid.org/en/packages/com.artifex.mupdf.viewer.app...
If its smallish like a sign where there is more art than text I'd image it (jpg, 150dpi) Small, prints OK and is quickly viewable. Maybe include the text copy along for indexing/ADA purposes.
A couple pages (brochure content), then I'd try to do a mobile web version and also offer the PDF if the style is something that adds to the content.
Long format (booklet, paper, guide, long story, magazine), where the audience is going to be reading it for a while PDF makes sense: you can style it, able to read off-line easier, and its no big to the user that they are breaking from the web to read. Been enjoying old magazines and comic books in the internet archive, can either use their on-line reader or download PDF. Either are OK, if I expect to travel, will DL some PDfs.
It's called epub. I read ebooks and documentation in this format, which is basically packaged html.
My use case for PDFs on phone are usually technical manuals.