To put it as simply as I can, from what I know:
Much of the basis for Aikido's unarmed movements are based on movements with weapons. The tai-sabaki of aikido as determined by the founder, is all based around weapons work.
Not all dojo use weapons. Not all dojo use weapons in the same way. BUT... if you can do the weapons work, then you should know the hand-to-hand work as well.
That's an over simplification, but I hope it drives the main point home.
MAN! I wish Patricia Hendricks Sensei posted on Aiki-web! Direct student of Saito Shihan with regard to weapons? SHE is the authority in this as far as I'm concerned.