I've tended to have a greeting on what i imagine (though I may be wrong) less status heavy routes, or less busy flights. I even had one friendly chap shake my hand once, which took me by surprise. I certainly do not expect the cabin service to be slowed or urgent matters around securing the cabin to be delayed so that someone can say hello to me. I know Ba get slated for lack of consistency, but something like a Gold greeting, if it becomes a routine service standard, will inevitably simply feel like a going through the motions, whereas at the moment, it seems more heartfelt, precisely because it does not happen that often. I'd say this is pretty low on my list of Ba priorities.