Markup UK 2019 included the Accessibility Matters paper by Tony Graham. The slides, but not the paper, covered the facts that:

The existing proceedings failed on every count except possibly the line height (but possibly only for some people). During and after the Accessibility Matters talk, there were multiple tweets from conference attendees about the difficulty of reading justified text. [LAPEYRE]

Figure 8. Tweet about justified text

Tweet about justified text

Given that, it was not credible to try for a ‘classic’ two columns of justified text with floating figures. Instead, the font size has increased – to reduce the number of characters per line – and the text is now left aligned. Hyphenation is disabled, so the only hyphens in the formatted text are from words, such as ‘over-enthusiastic’, that were written with hyphens. The proceedings now take about 10% more pages (currently 234 pages versus 212), but “we’re not planning on going to print”, so there's no printing cost from the extra pages.