There are sonic benefits to be gained by getting rid of the speaker-level crossover in a loudspeaker, instead filtering the signal before the power amps, the amps then powering the drivers directly. That requires the speaker be designed to be used in such a fashion, with the line-level crossover duplicating the standard speaker-level one, with no compensation networks for the drivers.
Bi-amping was recommended (by both Magnepan and their original distributor, ARC) for the pre-series .7 Magneplanars. The series .7 Maggies can not be bi-amped, for two reasons: The necessary speaker cable connectors are not present, and, more importantly, the series .7 crossovers are of series design, unlike those used in the pre-series .7 Maggies, which does not allow a simple "textbook" (1st, 2nd, 3rd, or 4th order filters) crossover.