Not explicitly mentioned here, but worth bringing up: Text width should always be constrained to a maximum width to optimize for human reading. Every book ever printed has text with set within the same range for a reason. Full width text guarantees most users will have a poor reading experience.
Newspapers use columns for the same reason, to not get too wide lines. Unfortunately I don't think I've ever seen a site use columns, even though CSS supports it. https://developer.mozilla.org/en-US/docs/Web/CSS/columns
Newspapers don't have scrollbars. So they use columns.
This may be why phone-apps are so popular, their content is designed to be viewed only through the app.
CSS columns is cool, I didn't know about it. But not sure where I would use it either.