They just pushed a reset switch on the parallel economy. But its not something that won't grow up again. This step was necessary. After this, they will have to bring down taxes for effectively preventing a parallel economy. And sometime in the future, something like a max-100Rs note will push users to use digital payments everywhere.
I think this is a safe experiment towards removing high-value currency notes. Won't be surprised if 2000 notes are recalled after some time and those might have been introduced just for convenience.
Its also a veiled attack on political parties, including his own (and they can't even complain)