If you are laying out text with narrow columns, using full justification without hyphenation is unlikely to result in an attractive document. Very narrow columns are most commonly the result of wrapping text around images. Consider the following unhyphenated and fully justified example:
Pretty ugly, right?
Compare that to a hyphenated version:
The hyphenated example above is still not perfect, but I suspect most readers will agree with me that it looks better than the unhyphenated example. These cases were created with a standard word processor (Mac Pages) by a person who is not a layout expert (me). A professional using real typesetting or layout software could undoubtedly do much better.
Many people prefer fully justified text, because it provides a veneer of profesionalism (since most books use fully justified text). However, fully justified is not the only option. Ragged text is a totally legitimate alternative. Ragged vs. hyphenated-and-fully-justified is a taste thing, but full justification without hyphenation (especially in a context of narrow columns, as shown here) should probably just be avoided.
Given that I have found myself giving this feedback several times now, I figured it merited a page that I could just reference. (And now you can too, if you come across egregious layouts and agree with my document aesthetics.)
Example images and text taken from the Wikipedia page on Necromancy: