Hope I haven't added to the confusion. I believe we're talking about releasing those cities as a vassal civ. I think you were following the discussion. I think some players are confusing this with vassals in general without realizing there is a difference.
For instance, I generally like taking vassals. It speeds up domination and diplomation victories and can provide help with research and war. I dislike releasing cities on distant continents as colonies even though they become vassals. That slows down those victories.
Colonies can lower maintenance costs but, for me, that doesn't make up for what you lose usually. Especially under State Property.