This somewhat worries me, because I am not sure if the trade was worth it, strategically speaking.
They're right-wing extremists. We know that for a fact and have known that without commiting cybercrimes. So what is there to learn?
Maybe embezzlement or similar, but.
We have to keep in mind that they have in fact become the victim of a crime, which they (best case) will spin to their advantage.
Worst case they will use it as a justification to commit such and other crimes themselves.
I don't think being hacked by an anonymous entity grants much political advantage? If anything the downside is shifting the overtone window by dumping all the far right takes on the broad public and making them a bit more familiar.
I think part of the advantage is providing public evidence in favor of a Verbotsverfahren, e.g. the process of banning a political party for being counter to the principles of the German constitution and with that, pressure towards the state organs to stop ignoring the threat and finally do their job.
They commit all the crimes already. If afd was anything but a political party, the security agencies would investigate them using those measures.