I use a controller when im fishing, or sometimes when im lazy and playing a low level class. But I think im doing like 10% of what I could do with my keyboard when im on a controller.
Targeting the target I want to target takes ages, and sometimes I target my own party and sometimes I just sheathe my weapon in the middle of battle, and well..

it was great for light farming though as a summoner, I figured out how to use 3 dots and fester and ruin and that was enough to kill garuda!