Smartphones have become so sophisticated that they are for all intents and purposes miniature computers with the ability to make and receive voice calls -- which may be one of their less commonly-used features. Like the cell phones of decades ago, dumbphones are used mostly for calling. The devices typically enable texting, albeit through methods that don’t require a full keyboard such as multi-tapping or text on nine keys (T9). Some dumbphones include features such as MP3 players and simple games, in which case they are sometimes called feature phones.
Dumbphones don’t require data plans and are typically much cheaper to own and operate than smartphones. Because they don’t have many features, the devices have lower power requirements and can run for several weeks on a charge. With their limited connectivity, dumbphones also provide a security advantage over smartphones.
Dumbphones initially targeted the senior demographic whose members often found smartphones too complicated to use. However, the simple devices are becoming more popular across all age groups for people who have tired of being constantly connected. In the United States, 24 million dumbphones were purchased in 2015, and the market continues to increase.
See the Wall Street Journal's report on the return of the dumbphone: