When shooting a carefully staged macro scene, the dedicated macro lens will have a wafer thin depth of field. Without Focus Bracketing, if I've made the artistic decision that I want the entire scene in focus, then I will need to compose, focus, shoot, refocus, shoot, refocus, shoot, etc. Perhaps as many as 40 times or more.
On my (wife's) RP, I simply need to set the bracket to 40 images, compose, and shoot.
Yes, it's still on me to combine them all in post, but the feature itself is useful, and can save time and tedium.
There are also landscape applications as well.