The clarity in writing is not just a virtue. It is the essence of communication between writer and reader. This is true whether one weaves a fable, explains complex philosophy, reveals scientific findings, or gives directions to a party.
To be understood, the very best writing needs to be utterly clear, simple, and short. This takes skill and discipline to persist until one has things absolutely right. But then, the reward is writing that the reader understands, believes, and acts on.