I mostly read manuals on a tablet, typically inside a book app (even if the file is a pdf). So, I still want the manual formatted the same way as a printed manual. I do also look up things in manuals on the computer.
Although they make a lot of sense for updates and searchability, I'm not fond of online only manuals. I find those very hard to read for learning, even if they are adequate for referencing on the fly.
Poll should include answer "only small part of it" or similar
I agree. I marked 'sometimes' - but that is that sometimes I'll print out selected parts of a manual, or special extra sections with lists of functions.
Ideally, my approach would be to start exploring a library or application without the manual and then, when I have questions in my head and a sense of how things work, I'd go through the manual page by page. When I do this, I've experienced benefits in my understanding and practice pretty much every time.
In practice, it varies. For a library containing relatively unfamiliar instruments, I'll look at the manual to learn more about them. For a library with complex parameters, I may look up those elements after a few months when I finally admit to myself that I don't know what I'm doing. This usually happens after someone on VI-Control asks a question about a library that I use regularly and I realise that I have no idea of the answer as I've just been metaphorically hitting the library with a hammer and listening to the sound that rings out.