I think we're talking about two different issues (support for modern CSS layouts and working around the frustrating limitations of existing email CSS). Anything that helps reduce the need to remember magic incantations (in comments!) to make your button render correctly in Outlook 2013 (made-up example) is a huge help! Worth noting that the title is slightly editorialized: the site itself doesn't claim to "end all your problems when creating email templates" - it just claims to "make your email templates compatible with all email clients." Only email providers themselves can solve the CSS support issue.