Q:

When is it ok (if ever) to provide a video example?

Video examples have a ton of drawbacks.  

Many people cannot view them at work
they could be hosted somewhere and then removed later, resulting in broken links.  
They're a waste of time when text will work
They could be the result of lazy writing

However, given that, is there ever a situation where a video link is acceptable?  
For instance:

animation glitches that are difficult to describe
supplementary info that is also described ("and if you want to see what I just described, I made a quick screencast")

I can see the argument where the drawbacks are similar to using JSFiddle or other external links, especially if the video doesn't have audio. Just wondering if there is unwritten community consensus on this one.

A:

Your answer, on SO, needs to answer the question.  If you want to include a video in addition to that answer, you're more than welcome to, but if your post wouldn't [attempt to] answer the question without the reader following the link to the video then it would be Not An Answer and would be subject to deletion.

A:

I think embedding a gif could counter most of those drawbacks.

Don't need to rely on an external website which can be blocked 
No broken links
Usually short and to the point
No sound; you still need good writing.

Since you cannot do a voiceover, text will still be mandatory. An animated gif will only be there to show what you cannot express correctly, not replace your entire post.
There's probably multiple free screen-gif-recorder on the web, personally I use LICEcap, which is open-source.
As an example, here's me typing the beginning of this answer:

It took about 10 seconds to setup.
In the past, I recall having used gifs at least once, on this answer, to support something which appeared unclear to me.
But even if it can be a great visual aid, it is still pretty distracting/annoying, so use sparingly.

A:

Additionally, glitches and other 'moving' problems have been successfully conveyed by animated gifs of just a couple of frames.
To me, videos take too much time to make and watch. I cannot quickly grasp the key element of a video in order to decide whether that answer is worth viewing completely. With text, in general, I can.

