Advantages of hydro-mechanical drain cleaners are their eco-friendliness (most use only tap water), their ability to dislodge and remove clogs like sand or cat litter that 'back-fill when using a conventional snake, and their friendliness to plumbing joints.
Disadvantages of hydro-mechanical drain cleaners included limited reach into drain plumbing, and the necessity of a water source to act as the motive agent.