Footswitches are very handy when you have an amplifer with two channels. I use this in my Fender Champion 100 to change from clean to distorted, I can also turn an effect I set either on or off. I prefer footswitches to a pedal because having two channels, you can make sure that both channels are equally balanced out and those are the only things you have to sort out, you don't have to spend ages getting the levels right on the amp and then on the pedal. With a footswitch you only have to plug in.
If you have a two channel amplifier and you don't want to waste your time with a pedal then buy a footswitch.