"Could anyone please give me an example of a process grating a Role permission to dispose/transfer a whole or a part of a Domain? Any other comments on this are most welcome." Disposing of..." falls under the rules for resource allocation, which by default belong to the Lead Link of the circle. The stipulation that you can't dispose of a domain just because you control it, is to cover situations in which a role has a "website" domain, but that doesn't give them the authority to sell the website or domain to someone else. On the other hand, if a role had a domain like, "List of approved vendors," but things changes such that you no longer needed vendors, then it seems reasonable that the domain owner could delete that list. So the distinction is really to cover assets.
"Why you don't add to Lead Link (LL)..." You nailed it. One addition, since we are pushing against the paradigm of "manager is leader" then it's particularly important to have an explicit rule that prevents you from making that role more confusing.