It will be ironic if AfD wins and then pushes their right wing viewpoint to the max to everyone.

There will be immediately be a "no wait, you can't do that" backlash from the same actors that are proposing this.

It's part of the scam, they actually want the AfD to later have that power so that they can say "Hey, look at what these fascists are doing, vote us back with urgency to prevent more fascism".

Win-win for the CDU/CSU and the AfD, the CDU gains power and has a boogeyman to use to scare voters into voting for them.