When someone proposes what we should do, where by we he implicitly refers to a large group of people he has no real influence over (as in the banning AGI & hardware development proposal), I'm wondering what is the value of this kind of speculation - other than amusing oneself with a picture of "what would this button do" on a simulation of Earth under one's hands.

As I see it, there's no point in thinking about these kind of "large scale" interventions that are closely interweaved with politics. Better to focus on what relatively small groups of people can do (this includes, e.g. influencing a few other AGI development teams to work on FAI), and in this context, I think out best hope is in deeply understanding the mechanics of intelligence and thus having at least a chance at creating FAI before some team that doesn't care the least about safety dooms us all - and there will be such teams, regardless of what we do today, just take a look at some of the "risks from AI" interviews...