My personal use case was that I tried changing my Wordpress Unmanaged Multisite's domain from the Cloudron's Dashboard and it totally broke the container (redis freaked out about the URL change during WP starting up) to the point where I couldn't even get a web terminal running on it so I had to clone a backup as a "new" subcontainer. If Cloudron had web hooks, I could code a WP plugin to listen for your "URL Change" function and hurry up and change all of the needed values in the database before the whole installation breaks. Of note, I am running multisite so maybe that's why your URL changing didn't work. I haven't tested it on a single site installation yet.

There are a lot of other use cases for this (like sharing access to singular containers between two cloudron instances for example and have their status get updated in real time on both servers the master and the secondary) - this is just the one that popped up in my mind. I'm genuinely surprised your new "multiple cloudron unified dashboard" branch doesn't use webhooks (or does it)?

Side-note: You could also use them also to change the subscription URL at https://www.cloudron.io/console.html#/userprofile?view=subscriptions if there was a webhook that for when a user changes there base URL (just noticed that I changed mine but my subscription name on the site stayed the same with the original URL, which no longer works).