No, my dear Croatian stallion
, there are some legitimate things here. It is early and my coffee hasn't kicked in yet. But, i'll try to enlighten you a bit.
It is not all about power power power power power power all day long like our friend Peng's been singing about. There are other variables.
As i said earlier, it can benefit some speakers with certain design deficiencies (generally cheap-ish speakers with low quality drivers/crossovers) or dinky li'l 2 way bookshelves with 1st/2nd order crossovers which can easily get overdriven and produce a lot of distortion. There are many dudes out there who will put small bookshelves in a hometheater as mains (especially if they have subwoofers n all, whoop di doo) and beat the sht out of it.
Poorly designed 1st/2nd order crossovers can easily let distortion through from woofer to tweeter. Woofers themselves generate back EMF, which contain distortion products which have a low frequency component that passes back through the woofer crossover. They can also have a higher frequency component that passes through the tweeter's crossover.
Now, when you biamp, individual amp channels see a higher effective load impedance than (in comparison to one channel driving the entire speaker). This should reduce crossover distortion and overall distortion in such speakers. In other words, it should help a poor speaker or a more or less decent speaker in a low iq application (as i mentioned above).
Lower cooling load for individual amp channels can lead to less temperature variation --> better dynamic bias tracking and lower distortion (especially in receivers with a poor cooling design solution in place). This is a benefit when serious corners have been cut on a receiver, likely with a low end Denon dumdum receiver lol.
Biamping can also reduce the output current requirement, a.k.a reduce distortion for the amp's input stage, etc, etc, etc
Now, can these things be audible? Only your ears can decide. Typically, a dude with a low quality receiver and low quality speaker won't have a system that resolves enough (in general) to hear these things. But, it comes down to the individual choice of components one my have in his setup.