I don't see why you would not be able to use it there. I see it as not only advertising dustsweeper, but as getting the out about dustsweeper. I don't use it on all my post and comments, but I try to remember and use it in places where people may not have seen @dustsweeper.

Everything dustsweeper does is behind the scene's, so I feel that a small advertisement every now and then is worth it. They are not flooding steemit with advertising bots or anything, or auto look at what we did for you comments, so I like to sometimes give a dust gift, and advertise/promote them on occasion.