I am much different than Donny....

I see the value of pedals...they add what are not possible using our fingers (volume/expression)..bringing in a "color" sound etc.

Multi keyboards was a factor in the 80's...
If you wanted to work in our area... you better play left hand bass, have decent sound (piano/Rhodes), and a synth for "color"..
This usually translated into 3 keyboards..
Polyphony was the other factor.. most keyboards were 6 voice .. So we added keyboards and rack gear to add polyphony.

we also blended our sound with rack modules , different brands combined for our "sound"..

True today we can handle all this with one keyboard... the keyboard needs to be a quality keybed with key range (76/88).
Pedal options too..

I would definitely use two keyboards on a job... I understand we get lazy with hour gigs and travel light... but if I am doing a 4 hour gig the extra 5 minutes to set up 2 keyboards that add a benefit
and enjoyment for me , the performer...is well worth it..

As Bachus mentioned two keyboards with different key action also comes into play...especially if you want weighted keys for piano, and a synth action for organ and color..