People keep doing the same mistakes but with "new" technology.
Are we really evolving software or are we just increasing the technology dependency and complexity threeshold, to do even the most simple things we already used to be able to do easly and many time with a lower technical and economical cost!?
Ask yourself, some of this questions:
- Are you sure that the third party JS framework aren't on compromised servers?
Have you ever used JQuery, while including the code from JQuery servers?
(If your answer is yes, you've already exposed your users to code on compromised servers)
- Do you believe your site will never fail if a third party hosted framework for some reason is not accessible or becomes broken on some user-agent you haven't tested (nowadays it's common on mobile environments)?
- Do you want your content to be indexed by search-engines?
- Do you want your content to be preserved for the future by the Internet Archive and others?
- Do you believe it's fair to impose the user more processing of untrusted code, just for the sake of "eye candy"?
Maybe these other articles can explain better, or complement my point: