I am going to declare a bounty on a question simply because I hope it will additionally stimulate at least somebody to think harder on it.
Among the reasons I could choose is "Draw attention", which says "This question has not received enough attention". Now this is not really true in my case, as in a week it got 143 views, 5 upvotes and 4 favorite marks.
So I think one should either add another reason (something like "stimulate more thinking on the answer", don't know) or, more likely, change the text under "Draw attention" to include the situation as above: when the question is obviously received with interest but I would like to inspire more activity.
Or I just misunderstand the very sense of those bounties?