Almost all users find that the use of a bong/water pipe with fresh water provides a smoother, less intense hit. When drawing in a large volume of smoke from combusted material, it can help for it to pass through a bit of cooling liquid before hitting the lungs. Water pipes do provide a bit of relief, but the size of most bongs allows for the implementation of additional features that help to cool off the smoke.
Bongs can include ice catchers, percolators, diffusers, and more that help to disperse and take the edge off of your hits. These accessories usually do not increase your glassware's overall maintenance, but it will definitely keep you from wasting time hacking and coughing.