User blog comment:Rupert Giles/Layout Changes: Breakpoints and Typography/@comment-25693582-20150519222157/@comment-126761-20150519230757

While we do believe they are immediate improvements in a variety of cases (e.g. line length), the long-term is where much of the improvement will come from. With articles designed around a relatively consistent layout, editors will know that their edits will look good for everyone - you won't have articles that look weird for the largest screens or the smallest screens.

We realise this may not be quite as obvious at the scale of individuals - many users only use one or two devices. But each day, thousands of very different devices view Wikia at all sorts of different sizes, and it is increasingly difficult to provide them with good experiences with the previous kind of layout.