Why would it fail today? If I can't serve an asset then my whole server is down.
If you are an e-commerce site serving hundreds of images worldwide then CDNs make a tonne of sense.
If you just have a simple site or SaaS getting decent traffic, why add a failure point by including your choosen JS with a CDN. No one batts an eyelid when you add ten images to the homepage but somehow a single, much smaller JS file is too much extra load. It doesn't stand up to reason.
