Not that difficult, but it’s still a separate dependency (with python requirements). If the goal here is a Caddy competitor, then IMO it’s missing the mark in terms of “one stop shop”. What’s the killer feature?
On the python requirements: I've always been satisfied with Bash implementations of ACME. I use dehydrated from the very beginning (when it was still called letsencrypt.sh) and lately started using acme.sh.