Is okay to use columns or other ways to layout the content so that it fits in one page?

I think the F.A.Q. tries answer to this question with the line "For example, Tunnel Goons (by Nate Treme) is over two smaller pages, and most 24XX games (by Jason Tocci) are across three half-pages, but you’d be hard pressed to argue that philosophically they aren’t a one-page RPG, especially if they can be printed on a single sheet." but I have troubles understanding whether the statement means that it is okay or that it's not. I'm not sure whether my confusion arises from my my non-native English level or if the sentence just is not written so clearly. In any case, I would highly appreciate if someone could clarify to me how this rule should be interpreted.

As long as it fits on a single page, you can lay it out however you like. Using columns and/or separate sections is a great way to make it more readable.