Why steam cleaning instead of dry or any other method?  The depth of cleaning and the removal of residue are the two main factors.  If your carpet were 6 months old and had some light top soil on it, dry cleaning would serve you well.  However, it will never have the depth of cleaning achieved with professional steam cleaning.

With proper training, equipment, and compounds, most soils and spots can be extracted from the carpet without damage to the yarn.  Dry cleaning chemicals left behind can be detrimental to your living environment and personal health.  With a professional steam cleaning followed by a rinse, there are no residual soaps or compounds left in the carpet.