I think metadata is defined as "data about data". And channels are not data.
Atom and Refs support metadata and they are mutable containers for values. I see channels similarly. It would be nice to be able to attach debugging metadata like what created the channel, a name for it, etc.
I do find the debugging use case compelling. If you opened an ask for it, I'd upvote that.
In the mean time, could you reimplement the channel protocols and just have them delegate to an internal channel? Then implement IObj on top?
That's what I did, and I implement IReference