They’re not identical. Performance Switch will ‘flex’ on all presets, according to the fixed function (& trigger ‘rules’) in that particular algorithm or group. Set expression pedal (AKA HotKnob) can be a superset over any parameter combination in that algorithm. It’s a very powerful feature; one that I use all of the time.
Effectively, OFF is equivalent to the Heel position, and ON corresponds to full Toe on an expression pedal. Instant switching between the two extreme (sets of) values. So, anything that’s been mapped to expression pedal control can be saved (per preset), and remains switchable externally. Two-presets-in-one (HotSwitch-like); instant stabs of effect; pre-record looping mixes; rhythm / lead shifts; preset ‘morphing’; etc.
