Not just API charging
Never use 3rd party APIs or code at runtime. Have all the code on your own server or instance.
Web sites using APIs / 3rd party fonts / 3rd party scripts etc are nuts.
Apart from the future potential to be charged, there is the Websites are awash with using 3rd party servers at runtime. It's a security and privacy hole apart from the issue in the article.
Another reason to be suspicious of claims of cost savings with Cloud Computing. Service providers want profits. WIMPEY.