Mostly to serve as an alternative to the entirely useless Gallant Slave nanoline.
Keep in mind that untill 220, there's quite a few playfields where crats can't get useful charms, either because the mobs all suck, or can't be charmed.
Allowing crats to take charms beyond a single zone would be rather nice as it fills a rather large gap.
So from a gameplay perspective, it fits perfectly. From a RP perspective, perhaps less... who cares, though? If I recall you lot got blockers and a shovel!