Is Amazon's S3 the cheapest streaming video hosting out there?

While researching CDNs for storage and delivery of digital video, I found that at least one major user-generated video website provider is using Amazon's S3 service for delivery of Flash video over HTTP. For http delivery of lots of clips on-demand, S3 is apparently doing the job.  The costs are astonishingly low:

• $0.15/GB stored per month
• $0.18/GB delivered (or less)

A look at Dan Rayburn's recent blog post listing streaming CDN vendors shows some of the streaming heavyweights, with broad networks of origin and edge servers optimized for real-time media delivery.  Akamai, for example, pre-caches media content close to the network's edges, making videos load quicker. For a site that's advertising-funded, fast loading pages can lead to more page views, which equals more revenue. 

But, S3 is an option I hadn't thought of for online video.  There's no support for the RTMP or RTSP streaming protocols, but many sites are just fine with HTTP download delivery these days. (Streaming vs. Downloading - What's the Difference?)  While it may not be optimized around realtime delivery, it certainly offers unlimited scalability at rock-bottom prices.  And options like its rich developer API and BitTorrent integration could be an asset to a comprehensive media delivery strategy.  It's certainly an option worth looking at.