Well, if you can't stop people from using a superweapon for bad causes, it may be an improvement to see to it that it's also used for good causes.
The original question was:
Do you really think encouraging this idea in general is good?
That is: assuming it is possible to reduce bad uses at the cost of also reducing good uses, should one do so?
Your reply seems to assume that the bad uses can't be reduced, which contradicts the pre-established assumptions. If you want to change the assumptions of a discussion, please include a note that you are doing so and ideally a short explanation of why you think the previous assumptions should be rejected in favor of the new ones.
I posted in Practical Ethics, arguing that if we mentally anthropomorphised certain risks, then we'd be more likely to give them the attention they deserved. Slaying the Cardiovascular Vampire, defeating the Parasitic Diseases Death Cult, and banishing the Demon of Infection... these stories give a mental picture of the actual good we're doing when combating these issues, and the bad we're doing by ignoring them. Imagine a politician proclaiming:
An amusing thing to contemplate - except, of course, if there were a real Cardiovascular Vampire, politicians and pundits would be falling over themselves with those kinds of announcements.
The field of AI is already over-saturated with anthropomorphisation, so we definitely shouldn't be imagining Clippy as some human-like entity that we can heroically combat, with all the rules of narrative applying. Still it can't hurt to dream up a hideous Bias Demon in its mishaped (though superficially plausible) lair, cackling in glee as someone foolishly attempts to implement an AI design without the proper safety precautions, smiling serenely as prominent futurist dismiss the risk... and dissolving, hit by the holy water of increased rationality and proper AI research. Those images might help us make the right emotional connection to what we're achieving here.