If ISPs (e.g. GoDaddy, Network Solutions) supported a REST API to DNS then applications like Google For Domains wouldn’t have to throw users to the wolves when it comes to configuring CNames and aliases.
Instead you could just give your credentials to Google and they could update your DNS entries directly. Most ISPs discourage direct fiddling with users DNS entries (for good reasons), but with the ability to customise your URL now a feature of Google for Domains, the need for non-skilled users to access this data is becoming more important.