by mjd83
The simple answer is that it allows for specialization. Most scenarios are considerably easier when you have one deck that can devote to combat and another that can devote to questing/threat reduction/etc. This is in contrast to a solo deck where you cannot specialize because you have to balance everything in one deck to be successful. Also, one deck can generally pick up the slack when another is struggling.. something not availabe in solo play where a bad round can easily be unrecoverable.This specialization advantage seems to outweigh the doubled numbers of encounters each round.