NEM uses a permissioned private blockchain so it's definitely not for the privacy advocates.

That's wrong.

The main NEM blockchain is permissionless. However, there is a project called Mijin which provides a permissioned version of the NEM blockchain to manage who can access it. Furthermore, the Mijin blockchain can then be connected to the public chain.

Mijin is the utra-fast release of NEM. Now they are working in a super-ultra-fast release, called Catapult. One time this year, Catapult will be merged into the public chain, but there are now some uncertainties about how to do with it, as Catapult is completely a different beast.