Knowing the true name of a shell makes it easier to consult scientific literature for supplemental data about the habits, biology and the distribution of the shell. Common names are not very satisfactory, because, people in different locations and countries may use the same name for different shells. Carolus Linnaeus was universally accepted and is used for the classification of all forms of animal and plant life, including fossils. If you have seen a Helmet Shell you have seen one. The cowries, with their glossy, china-like shells are perhaps the most attractive of the gastropods.
Cones are also extremely beautiful as are the volutes and murex, all jewels of the sea.
Some such as the nudibranchs, lack shells. Some oysters produce valuable pearls and the clamshell becomes a giant in some locations such as on the Great Barrier Reef and Indo-Pacific waters. They have even been used as baths, baptismal fonts, and taro and tapioca has been crushed in them for hundreds of years by islanders. For many years there were tales of deep sea divers and islanders having an arm or foot caught between the giant valves but this was said just to have been exaggerated tales. In the 1980's near Port Moresby, Papua New Guinea, scuba instructor Diane Pearce nearly lost her life demonstrating to some student divers a giant clams reaction to her putting her hand inside the shell and promptly withdrawing it.