Note that active bi-amping is most useful when the crossover frequency between the woofer and the high frequency driver(s) is below 400 Hz. The advantage here is that you don't have an inductor in series with the woofer which would represent a high resistance, added to the resistance of the cable between the amp and the speaker cabinet. The high resistance inductor would have the effect to reduce the amplifier damping action (Damping Factor) which is of most importance at low frequencies. In my opinion, if you want a tight bass, active bi-amping is the only way to go with low filtering frequencies.
I am going to start a campaign to outlaw the term "active bi-amping".
I assume you mean "amping a speaker with an active crossover" which, in the case of a 2-way design, just happens to involve 2 amps (well, two channels per speaker).
My active speakers are 4-way; so I have 4 2-channel Yamaha P-series amps powering them.
There are some advantages from an amp standpoint (since the crossover no longer needs to convert energy into heat to the same degree, there are some gains); but really, it's about what the active crossover brings to the table... not the amp.
If you really want a neat one: take a look at the back for a McIntosh XRT2k. Unless I misunderstand what I'm seeing, the woofers are run in parallel with separate posts. So when you run separate amps for the woofers (up to 4) you raise the resistance and lower the power draw. In short: you can get more power by adding more amps (which are all feeding the same frequencies).
So, I guess, that would be a valid multi-amp-benefit on that particular speakers.