I find weapons training to be beneficial. One thing that is a bit frustrating for me since I am new to everything is that some things are done different with iaido and using the bokken in aikido. The principles are the same, but some of the stances and movements are just a tad different. Sensei says it will make me more concious of my body and stance and that it will help me in the long run, but for now... it is just tedious for me to remember.
As with everything, expect to put in some hard work and practice.