Clearly it doesn't but this is a concept that is completely new in OH. There is no documentation for it in the docs yet. And while I admit to not reading each and every posting on this forum, I believe this is the first mention of a Channel trigger for Rules anywhere on the OH side of the ESH/OH 2 divide.
In this case the documentation for Rules needs to be updated as there is no mention of "Channel" as a valid Rule trigger.
Is this the new concept we have heard about that is intended to replace the old capability of the 1.9 Astro binding where it generates an event on a Switch at sunrise/sunset, etc?
Is one able to persist when these channels are triggered without creating a new Item (not bound to the channel since it isn't allow) and Rules to update that Item? I'm thinking of a use case where in a Rule where I may care if that Channel was triggered say five minutes ago. It feels like a lot of extra work for the users that didn't have to be done previously.
People have been using Switches for simple buttons in OH 1.x since the beginning. But your comment implies that we will be able to put a Triggering channel on our Sitemaps. Is there a new Trigger element in work or do we still have to use a Switch to simulate a Trigger?
And if we are concerned about the user changing the state a Contact can be used which has an implied "read only".
At a high level, I understand philosophically why a Trigger like this wouldn't be assignable to an Item, but I can think of several use cases off the top of my head where this makes things that used to be simple and straightforward in OH 1.x impossible or challenging in OH 2.
This is probably a larger discussion but since this Binding is the first to use such triggers this is the first time its come up.