A truly active crossover system will exhibit a much more obvious improvement in sound than either passive bi-amping or bi-wiring. Passive bi-amping has at least _some_ bit of justification in electronic theory, that being load sharing and a bit of isolation, but honestly, the effect of the passive crossover still being in series with the drivers nulls out essentially any benefit that this connection may have.

Bi-wiring is useless, assuming that your speaker cables are of sufficient size in the first place. Speaker companies like to tout their speakers as being bi-wire ready since this makes them seem more "high end", and obviously speaker cable companies like it too. But it's just marketing.