It seems to be a single-sided debate. When you mention keyword use, all thoughts normally go to the search engines.
Copywriting, however, is more about your human visitors than it is the engines. In fact, even the mainstay of SEO copywriting (keywords) is based on a need to spur visitors along as they work through the information on your site. If you want truly effective SEO copy, you'll take time to learn that keyword use goes beyond the search engines.
Let's go offline for a moment. Go get your telephone book. If you were going to conduct a search for, say, an office desk, how would you go about it?
You'd look in the Yellow Pages under office furniture. Next you'd drill through the ads in search of ads that specifically mentioned "desks" or perhaps the particular kind of desk you want.
SEO for Newspapers?
When looking through the inserts that come with your Sunday newspaper, your eye would be especially drawn to office supply flyers that featured the word "desks" or a picture of desks. Why? Because you've got desks on the brain right now. You're going to be especially sensitive to that word because that's the current need you're trying to fill.
The same, exact thing applies when someone searches online. Keywords started out because human Internet searchers typed them into the search engines, not because the search engines selected the terms. The same holds true today.
You don't just make up keywords. You use services and programs that allow you to research the exact phrases human beings are typing to Google, Yahoo! and other engines.
When you incorporate those words and phrases into your website copy, you're doing way more than attempting to boost your rankings; you're also helping to navigate the site visitor from the search engine to the right page of your site.
If you're the owner of the office supply store we've been talking about and you want to create a newspaper ad to sell a new line of desks you carry, what do you think might appear in the headline? The word "desk" or perhaps the phrase "office desks."
Why would you do that? There are no search engines to optimize for in the newspaper industry. You'll include those keywords because it makes sense to do so.