Legally, the only thing that happened is that the BfV can now use their whole toolbox of covert instruments against the AfD. The federal government, parliament, or a majority of states can always starts proceedings before the constitutional court to ban a party. Of course you don't want to do that if you have a flimsy case, but in principle there's no requirements at all.

Politically, it means that politicians have less of an excuse to not open proceedings.

Side note I doubt those 1100 pages are all the BfV has on the party: In their press release (the actual report is still classified) they only mentioned the AfD attacking human dignity, while for a court case you'd definitely also want to argue the wanting to dismantle democracy part, and if that was in the 1100 pages then the press release would've included language saying so (that's just how bureaucracy works in Germany, summaries don't randomly leave stuff out).