If the content is only accessible after you fill out a CAPTCHA, Google won't be able to index your content, and you won't have any visitors for scrapers to steal from you.

I suppose you could provide the content without a CAPTCHA if the user agent matches the crawlers of Google, Bing, etc. But it's still a bad idea because a lot (most?) of your users will bounce on the CAPTCHA, killing your ad revenue.