Over at the Emacs subreddit, floofcode complains that he doesn’t like the way visual-line-mode handles moving from line to line. He found that everything worked fine without visual-line-mode so he wondered when is visual-line-mode useful.
If you read his post, you’ll notice that he had visual-line-mode turned on globally. That explains a lot of his frustration. As nice as visual-line-mode can be, you definitely don’t want it enabled all the time. It would be a disaster when writing code, for example.
The thing about visual-line-mode is that it considers all the text between line feeds to be one long line and soft wraps the text to fit your screen size.That’s useful even when you’re just dealing with text locally but I find it essential for my blogging. If I set a hard line size, it gets carried onto my blog and really messes up the displays of people with smaller screens or windows such as those reading Irreal on a phone. With visual-line-mode, the text gets flowed to fit the target screen.
So the answer to floofcode’s question is that visual-line-mode is definitely useful but mostly when you’re writing prose such as in Org-mode. I use it whenever I’m writing prose but never when I’m, say, programming or using some other specialized Emacs mode. For instance, I don’t use it in my Org based tax files because they’re mostly tables and don’t include long sequence of text. I generally set it on a per file basis except for my blog where a hook recognizes blog posts and sets it and some other appropriate modes.