Hi appliedprivacy,
The certbot hook script was developed when we did not offer Managed DNS hosting for custom domains yet. Back in the early days, we only did dynDNS hosting.
We never got around to update the script, and native support from ACME clients is increasing (see Tools implementing deSEC). However, if someone wants to generalize our certbot-hook, we’ll be grateful for the contribution!
Stay secure,
Peter