I can't really agree with the statement that "the amplifier will have to
do
less work to produce more sound". Amplifiers are a constant-voltage
source,
so the amplifier will produce whatever current is required to achieve the
necessary output voltage at any given instant. The only possible advantage
I
can see with bi-wiring is if one of the drivers (the woofer most likely)
draws so much current that the voltage drop in the speaker wire would
otherwise affect the voltage going to the other drivers. Bi-wiring would
then provide a dedicated run for each driver to the constant voltage
source
(the amplifier). However, unless you were using severely under-rated
speaker
wire, I would expect this effect to be miniscule compared to all the other
effects that adversely affect the sound (the speakers themselves, the
room,
source material, etc.).

Come to think of it, the only possibility for interaction between drivers
would be in the crossover transition bands.