Single-column would require the font size to be increased to keep to optimal line length (https://baymard.com/blog/line-length-readability https://baymard.com/b

Single-column would require the font size to be increased to keep to optimal line length (https://baymard.com/blog/line-length-readability https://baymard.com/blog/line-length-readability), and increasing the font size would require more paper when printed.