A "transactional currency" is a "store of value" that is also used as a "transactional token" (aka You must have it to issue txs on the system).  Part of the reason it is a "store of value" is because it has value derived from being utilized as a "transactional token".  The other part is because it is limited in supply.  There are only 1 billion NXT.

It is my opinion that BCNext's intention was to reestablish the original ideals of the Bitcoin movement with NXT.  Bitcoin was originally intended to be a decentralized economy, but it turned into a centralized store of value.  BCNext knew people would hoard NXT because of its value as a "transactional token" on the platform.  This hoarding of NXT would cause a deflationary cycle to occur in the NXT economy if all purchases had to be made in NXT.  No one would buy anything because if they held their NXT, they would be able to purchase more later.  This would cause the NXT system to cease being a payment platform and become simply a "store of value" like BTC.  As you can tell from BTC's history, most people who own BTC don't spend BTC on purchases and if they do, they quickly re-purchase more BTC to replace what they spent.  BTC is NOT a payment platform, but a "store of value" ONLY.  NXT as a system was designed to be BOTH a "store of value" system (utilizing NXT as the "store of value") and a payment platform utilizing MS currencies.

I don't believe the MS was envisioned by BCNext as a way for people to make BTC clones or other "store of value" type currencies.  I believe he wanted it to be used in two different ways.  The first being gateways coming online and allowing people to use their national or local currencies on NXT.  The second being the creation of "social credit systems".  Imo, the reason "anti-deflation" was included in the "Transparent Forging/Economic Clusters" section was because "social credit systems" are "anti-deflationary economic clusters".