It's like if 6 month from now they release DRK for MRD then Darkknight job would be using a great Axe and that it. Meaning if you want to see dark knight use a Scythes they have to make a class that use Scythes then link that job to that class.
Which is why the armory system sucks.

Don't try to make sense of this system, people. Jobs were shoe-horned in over classes in 1.0 to make the game seem more "Final Fantasy-esque". There are serious longevity issues arising, and this thread outlines one of them.

It's also stupid that if a Monk picks up a staff-- a weapon Monks are traditionally trained to use to great effect-- they magically turn into a Conjurer for some reason.

For all the good Yoshi has done with XIV, not overhauling this hideous class/job/armory system amalgamation was a huge mistake. A new system should have been introduced that was designed from the ground up to fit the new game. Instead they just forced a square peg into a round hole.