The standard on/off button is a toggle which is useless for multifunction remote programming use.
If you want to make a command "all devices off" on a Pronto, you need to be able to send a "discreet off", to make sure it's off, and not that is it switched on if it was already off. Similar, if you want to make a button "Listen to a CD", you need a "discrete on" to switch the box on, no matter if it was already on or not.
For both scenario's, you can't use a toggle function.