Although a volume pedal may not seem like the most exciting effects pedal around, it can be one of the most useful pedals in a guitar player's pedalboard. Sure. It's easy to control the guitar volume straight from the guitar itself; however, sometimes it's easier to use your foot, especially if you're switching guitars or are using two hands for harmonics or some other technique.
Since there are so many places to use a volume pedal, several guitarists actually use two of them - one before distortion and one after. Placement of a volume pedal can be crucial in achieving the right sound. Typically, it's best to place them before delay pedals, though, since you don't want to cut off the delay trail. Several guitar players (Phil Keaggy, for example) will use the volume pedal for smooth swell techniques. Others may use a volume pedal to simulate the sound of a steel guitar. One thing is clear. A volume pedal is more than just an afterthought. It's a crucial component in any guitar player's effect chain.