This snow anchor from SMC has a cable permanently attached at the center, and is designed to be placed either horizontally or vertically, depending upon the snow conditions encountered.  The reinforced striking area prevents "mushrooming" of the end when pounding the picket into a vertical placement.  Shorter length pickets like this are ideal for firmer snow conditions.  Snow conditions vary widely and the strength of various types of placements is difficult to predict.  There are many different trade-offs with different types of snow anchor designs, depending upon the circumstances.  The right tool for the right job.  Just like everything else in climbing, proper instruction and practice in a safe environment is essential.