A continuous pedal action would be more versatile than switched input.  The advantages of Aux switches – or switching over MIDI – are the instant jumps between two parameter values, the ability to set specific limits on those values (or reverse them), plus a choice between momentary or latching behavior.

There are also ‘hybrid’ methods for overlaying a switch action on the expression pedal mappings. Ideally, you’d have both types of control (continuous & switching) available. Select one based on the effect that you’re after.