Is there value in posting a video of my paper presentation online?
You need to be sure that you are allowed to record presentations—as one of the comments indicated, many conferences prohibit such behavior.

If you are allowed to do so, it's usually for personal purposes, and public postings may be limited.

On the other hand, it may be possible for you to create your own version of a "podcast" with the talk using screen capture software. You can talk through your slides in greater detail than is possible in a typical conference presentation.

That said, I don't think there will be a huge demand for such a presentation.