True, in this case it is great, somehow mandatory, that it is fully self-contained :). However, dynamic content like the current power consumption and CPU load would still need be served by the origin, or cached at the CDN with short timeouts only.

Using CDNs was more an idea/suggestion for others who take this project as an inspiration to run their own website even with small hardware, unstable electricity supply and/or expensive/limited bandwidth, where a CDN can further reduce server load and traffic. Also when speaking about efficiency of the Internet in general, using small SBCs where sufficient, a CDN usually serves assets/content much more effective, given a network where a particular edge server is usually closer to the visitor than the origin server, and hardware that is specifically designed and run for that purpose and can be assumed to be highly loaded (less wasted power consumption). So as long as one trusts a CDN, or the content is not of any security or privacy concerns, it is usually a reasonable choice to make use of it :).