This is intentional.
The set of applications available through Google Apps has changed significantly since we added that checkbox — Google Docs is now part of Google Drive, for instance, and iGoogle no longer exists. More importantly, though, the applications enabled on any specific domain is now controlled by some settings in the Google Apps administrator panel, which we don’t have access to.
We’ve left that checkbox in place for domains which already had it enabled. For new domains, we recommend that you create CNAMEs manually through the DNS management page, as that’s considerably more flexible than having a fixed (and outdated!) set of aliases be created for you.