Carbon-Zinc batteries (sometimes referred to as Zinc-Chloride or Zinc batteries) are intended for low-drain devices. Low-drain refers to devices such as radios or alarm clocks which do not require a high power output. Carbon-Zinc batteries shouldn’t be used in devices such as a digital camera as the high power needed for these could cause the batteries to fail and even leak.
These are ideal in a situation where one needs to power multiple devices for one occasion, such as when buying many toys during the Christmas season to be used for a few days.