At least the first direct-brain interfaces won't work that way. They cannot recognize what you're thinking and transcribe it, that's way too hard. It'd be more analogous to having an extra limb (which you'll have to train extensively to be able to use it effectively) you can type/move the mouse with.

I'm fine with such direct brain interfaces, as long as they don't have to cut a hole in my head, or shave my hair off and put sticky stuff on my head :P