It seems to wrap correctly in landscape mode.
imo it highly depends on the medium. If your content is packed with distracting ads, flashing banners, other unrelated text from other stories, then its helpful to make the columns narrow to help you scan.
If you have a more focused experience around one passage of text, wider text lets you fit more on the page and make better use of paragraph breaks and subheadings
The only two types of books I can think of that are routinely read for purposes other than leisure - dictionaries and the Bible - are usually printed in multi-column layout from what I've seen.
When we published a print magazine we optimized heavily to save 1% on printing costs. 25% would have been suicide. And indie magazine buyers are traditionally a lot more price flexible than mainstream book buyers.
Many websites already have a limited text width.
Instead we should look at modern books. Without paying good money to use tools like InDesign, just use LaTeX with microtype together with the default margins. You will get the ideal width for text lines (about 60 to 80 characters), full justification with minimal hyphenation.
Especially for the definitions that are very short, for example when they only reference a more preferred spelling or a more prominent word that has the exact meaning.
You don't really want to reduce the number of sheets for your newspaper because size of the newspaper is an indicator of quality. But trimming off maybe 10% of a dictionary is worthwhile. Size of a dictionary is a quality indicator too, but the absolute production cost is more for a book so saving production costs is more pressing.
This is a totally context-dependent decision.