I'm not huge into drones, but I have one I use for taking photos of houses for real estate purposes. They're remarkably easy to fly, but they're kind of pissy to use because everything has to be charged, there can't be any flying restrictions in the area, and the weather has to be nice for you to actually fly the thing and get photos. They're also really loud, everyone will know there's a drone coming from quite some while away, and the battery life and range also isn't too good. So in the case some terrorist were to use one to attack us, you'd be able to narrow down the range to they were physically in to a pretty short distance, and with a decent amount of cameras or even microphones on the streets you'd be able to check who heard it first.
tl;dr less dumb than suicide bombing, but kind of expensive, loud, and the range isn't great8d4199