This is very important for outbound integration.
e.g. Someone is added to XYZ list, I write automation that calls my own servers webhook URL with customer data. I can then trigger any thing on my own server to be done because they where added to that list.
Without this 3rd part integrations (own built systems) is just about impossible.
Customer is Added to list ID X.
Send webhook to URL https://www.mydomain.com/webhook.php?listid=4&wait=5mins
The webhook URL should be changable for each instance.
I would also use this for WAIT 5 days and if still on list X send another webhook URL to me with https://www.mydomain.com/webhook.php?listid=4&wait=day5