From a "decentralized internet" point of view, I wouldn't like to have
a mirror going through a "big" CDN like Cloudflare. Morever, actual
mirror are plenty enough and fast enough.
On top of that, Cloudflare's HTTP firewall may block some
apt-get/curl/wget users[1][2] which
is not wanted for software repositories.
Also, Cloudflare's Terms of Service[3] state they're explicitly meant to
be used with HTML content.
2.8 Limitation on Serving Non-HTML Content
The Service is offered primarily as a platform to cache and serve web
pages and websites.
Unless explicitly included as a part of a Paid Service purchased by
you, you agree to use
the Service solely for the purpose of serving web pages as viewed
through a web browser or
other application and the Hypertext Markup Language (HTML) protocol or
other equivalent technology.
Use of the Service for serving video (unless purchased separately as a
Paid Service) or
a disproportionate percentage of pictures, audio files, or other
non-HTML content, is prohibited.
Even "cheap" CDN providers are more expensive for high-volume traffic
when comparing to
dedicated servers with unmetered bandwidth, and many servers are hosted
by
universities with large[4] amounts of bandwidth.
[1]: https://github.com/oerdnj/deb.sury.org/issues/1170
[2]: https://github.com/oerdnj/deb.sury.org/issues/1299
[3]: https://www.cloudflare.com/terms/
[4]: https://ftp.acc.umu.se/about/index.html
