I would use sustain more if I had three feet.
I like my right foot on the lead volume pedal, and the left to trigger vocal harmony. I have tried multi-pedal setups, but find myself having to think too much about which foot is doing what.
I've finally gotten to where I really don't have to watch, or think about, what my hands are doing, and too old to learn new tricks.
Sustain is a valuable "weapon" though, particular in playing piano. It helps notes ring until the exact time that they should stop.
DonM