Why the method matters at all
Carpet is not a smooth surface but a floor of millions of tangled fibres, and each method treats those fibres differently. Some wash with water; others lift soil by gathering it into foam.
The method affects three things you should know about: how deep it reaches, how much water stays inside, and the risk to colour and fibre.
So we do not say one method is better than another in every case, only that each has a place where it fits.
