[indubitably]

A controller is generally used because the driver will be more familiar with it, there is a second set of triggers (bumpers), and the driver can move around a bit more with it. That being said, thumbsticks generally feel a little awkward for tank drive control but are more comfortable for arcade and omnidirectional control. Also, even though drivers may be comfortable with the controller itself, the amount of time from input to a robot's response is significantly larger than in most video games so there is still some things to get used to.

Joysticks offer a larger range of motion which can prevent the driver from being as erratic as they might be with a controller. They are usually the preferred input for tank controls but still feels comfortable for arcade/omni. Also, drivers usually feel like they can emphasize their input a bit more which is satisfying in intense FRC games.