This whole topic kind of flies in the face of what an elder at my wife's kingdom hall, Brother Smart Engineer, said when I showed him a picture of Pastor Russell's pyramid memorial tomb I took when my wife and I visited Pittsburgh, PA last year. He said that the one thing he loved about the witnesses is that they do not continue to believe in things if they discover the truth about them.
Simply put, "...we don't continue doing things like celebrating Christmas just because it feels good to us..."
Yet this whole phrase, "Even if it's not the truth, it's still the best way to live..." is no different than what they might encounter when a householder says that he or she loves his or her religion and will not change.
My wife has actually said this phrase, a fact that I might point out the next time I have a conversation with that elder, Brother Smart Engineer.