3,Gov will ban it, because it is anonymous and can not be controlled. People can use btc buy illegal goods like drugs and guns, and may not pay tax. Or terrorists will use btc to fund terrorism activities.
you are right. With Bitoin being banned, what else money should criminals use? Did you ever see a movie where the bad guys didn't use Bitcoin? I didn't. So you are right on this point.
At last, we can pay off those IS-types, after all, the beheadings are good entertainment. - OR, you can pay some coins to the welldoers at the same geographic location, who supplies medical treatment and food to some widow with five hungry kids. Great, don't you think?