Readability
The search engines are trying to give their users the best possible user experience in terms of their SERPs.
Whilst search engines can't necessarily distinguish a well-written, meaningful sentence from a series of words that is grammatically correct but reads as gibberish to a human being, they are striving to provide the most relevant and accurate results for any search phrase.
You should ensure the visible text content does not suffer from being optimised, then, by reading it aloud to determine both authenticity (i.e. text generated to be read by humans, not simply for the benefit of search engine spiders) and readability.
Search engine friendly copywriting is a skill of its own, and should not be dismissed lightly when generating visible text content for your site.