Perhaps I'm missing something but what's special about Cloudflare here?

You can use a boatload of providers for automated DNS-01.

There's a relatively short list supported by certbot out of the box.

One tool that can be used in a deployment hook which supports the API of several dozen DNS providers:

* https://github.com/dns-lexicon/dns-lexicon

The list of API integrations provided by the lego project looks quite impressive. https://go-acme.github.io/lego/dns/index.html