The "just look at it and you will know if it's working" is fine in a test environment or a small shop.  As customers push Domo Everywhere out to broader audiences it's entirely possible that users will see errors that administrators simply wont -- different browsers, different networks, different embeded cards, different SSO permissions, etc.

A programatic way to know when embeded cards do not serve properly would be very helpful allowing us to fix these sorts of issues before users report them or worse yet before they simply start ignoring Domo cards that are broken.