"What the prescription specifically does is that it means membership, support or active involvement in the network that is identified as JAD is therefore a prosecutable offence," Raffaello Pantucci, Director of International Security Studies at the Royal United Services Institute (RUSI) told RFI.
JAD--as it's known--pledged allegiance to the Islamic State armed group (IS) shortly after its creation in 2014. The group, already recognized by the US as a terrorist organization since last year, was charged last Tuesday with being an organisation responsible for widespread terrorism and the loss of lives.
"It's very significant," says Chris Chaplin, a fellow at the London School of Economics.
The ban ties into the government's new anti-terror laws that they passed in May, and is part of efforts to ramp up security ahead of the Asian games in August.
"Now that the organization has been banned, just being affiliated to it and being a member, allows them to be detained for a longer period of time," Chaplin told RFI.
"JAD and their activists are now charged with organizational responsibility," he adds.
This is only the second time that Indonesia has done this. In 2008, Jakarta banned the radical Islamic group, Jemaah Islamiyah, because it was found guilty of committing terrorist acts.
Ban could embolden JAD
The only problem is that this repression could backfire, warns Chaplin.
“The more you clamp down on these groups and the more restrictive you become, the more they might be able to play the sympathy card," he comments.
Another risk is that the ban could embolden JAD, says RUSI's Pantucci.
"The thing about choosing to prescribe the group however is that you are now acknowledging that it is a group," he explains.
They're no longer just "local supporters of ISIS, (...) by giving them a structure, you’re giving them substance and strength."
The more dangerous of the IS-affiliated organizations in Indonesia, JAD has however been unable to match the scale and scope of previous terror attacks, notably the Bali bombings in 2002.
That doesn't mean the threat of IS is to be taken for granted warns Pantucci.
"JAD is already a terrorist network, so to some degree they don’t really care if they’re prescribed or not because what they’re doing is already illegal," he says, suggesting that the group may continue albeit under a different name.
Islamic State in Indonesia after ban
For his part, LSE's Chaplin reckons that the ban would make it more difficult for the Islamic State armed group to maintain a foothold in Indonesia, but suggests that the Philippines faces a far bigger threat from IS than Jakarta, "as the battle for Marawi, clearly showed."
The ban has other drawbacks, notably the fact that it doesn't address the problem of radicalization in prisons, or Indonesia's porous borders, says Chaplin.
"There's a potential for people to cross over from the Philippines and even Malaysia into Jakarta, and for new groups to take over from JAD."
Pantucci meanwhile concludes that, "we should see the prescription of JAD as a response by the Indonesian authorities in part to deal with the problem they’re already managing at home, but also to make sure that they have all the tools ready, should they suddenly see the threat from Syria and Iraq acutely express itself back home."