Very nice and simple.

But maybe I'm a bit confused as to the simplicity.

Don't you just have some kind of actor responding to events related to an address?

So in general,  if we have an actor that has channels,  and we treat each channel as a bitcoin address, is this effectively what you are doing?

Is this the same thing what Electreum proposal is saying?

The only real technology that is needed is a colored coin capability.  Beyond that, all advanced protocols can be handled by actors/agents.