Seems quite a lot of people (including me) use the m-vave chocolate footswitch. To iphone/ipad apps, the chocolate can be connected directly via bluetooth. With the Kemper you can go wireless using the bt-receiver/transmitter sold separately.
But it would be very nice if the Kemper (Player) would support MIDI via Bluetooth directly, so that devices like the Chocolate but possibly also IOS/Android Phones/Pads running MIDI-Apps could control the Kemper.