Utility of bow booster

Hi guys, i would like to know whats the use of bow booster after u have 4th job, as hurricane it’s not affected from it, does arrow rain get benefits from it or some other skill?

thx for answers

 

arrow rain and inferno gets affected by it

 

I have read before that attack speed matters for the start-up animation of Hurricane.

It matters very little, don't skip it tho!