You may have the good luck of never having had your hard drive crash on your computer. It has happened to me twice and if you don’t backup your computer or store your valuable files and videos on a cloud-based storage system, you are in big trouble.
The other reason for using Amazon S3 is because we have membership sites with many videos. Have you been on sites where the spinning wheel goes on for a long time for the video to load?
This loading problem rarely exists, if at all, with Amazon S3. Plus, the cost to store your folders or “buckets” as Amazon calls them, is a real bargain unless you have thousands of people watching thousands of videos per month. That would be a nice problem to have anyway!