Using pages to display text is fine. I regularly use space to scroll a page down when reading a long text in the browser because it is more pleasant than constantly scrolling. But fixed pages should not be part of the document markup in most cases. Reading a PDF on my phone is not a pleasure just because I can't just flow the text to fit my device.
I do most of my long-form reading on devices that don't have a space key.
I am not talking about fixed pages or clickbait websites where you have to scroll anyway and then click a "Next" button, but about having a flexible way to enable pagination of content.
That pagination is one of the reasons why for me the best way to read something like the stories in http://longreads.com/ is on Instapaper (or a similar tool).
