[citation][nom]americanbrian[/nom]Hasn't SSL been broken recently? In what way does it offer any sort of protection?[/citation]
Some researchers have found an exploit but have not publicly released the details of their implementation as far as I know. The benefits of the HTTPS connection for unsecured Wi-Fi are, as stated in the article, just a bonus. The real benefit (for Google or the end user, you decide) is that your search query isn't sent to the web server when you click on its associated search result.
[citation][nom]de5_roy[/nom]this seems to be the real reason. squeeze more money from ad companies by charging extra for the ssl data, increasing ad revenue.[/citation]
Ad companies? AdWords campaigns are run by massive corporations right down to sole traders. I don't think this will be used to artificially inflate cost per click, but if it pushes more companies to use AdWords so that they can receive meaningful Analytics data then CPC will inevitably rise. Remember though that it's only for users who are logged into a Google account at the moment, or those who explicitly choose to visit Google via HTTPS (the latter is almost nil).
Personally I think that Google is trying to make life harder for SEO analysts, both "good" and bad. Google doesn't like SEO analysts; they manipulate search results unnaturally. SEO is often sold as an alternative to PPC that is cheaper in the long run and with a higher ROI. It's in Google's best interest to deter companies from dropping AdWords in favour of SEO, because Google makes a bucket load of money from AdWords and absolutely nothing from SEO.